diff --git a/CHANGELOG.md b/CHANGELOG.md
index f4de5c6..c43a7b8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,9 @@ IMPORTANT NOTE: This version only works on CACTI 1.x++!
 
 --- develop ---
 
+* Make configuration saves and repairs atomic; coordinate writes, registration and deletion with destination-directory locks and report failed editor saves
+
+* Add editable map notes with alignment and sharp text at logical map dimensions
 * Fix editor placement reset, destructive action controls and theme contrast
 * Reduce gallery preview cards by 20% while preserving generated thumbnail resolution
 * Add a searchable node icon picker and bundled enterprise site icons
diff --git a/js/editor.js b/js/editor.js
index 4ee8f47..17080cb 100644
--- a/js/editor.js
+++ b/js/editor.js
@@ -545,6 +545,9 @@ function wmEditorReturnUrl(target) {
 }
 
 function attach_click_events() {
+	$('#xycapture').off('click.wmnote').on('click.wmnote', function(event) {
+		if ($('#action').val() === 'place_note' || ($('#action').val() === 'move_node' && typeof WMNotes !== 'undefined' && WMNotes[$('#param').val()])) coord_update(event);
+	});
 	$("area[id^='LINK:']").attr('href', '#').off('click').on('click', click_handler);
 	$("area[id^='NODE:']").attr('href', '#').off('click').on('click', click_handler);
 	$("area[id^='TIMES']").attr('href', '#').off('click').on('click', position_timestamp);
@@ -559,6 +562,35 @@ function attach_click_events() {
 	$('#tb_mapstyle').off('click').on('click', map_style);
 
 	$('#tb_addlink').off('click').on('click', add_link);
+	$('#tb_addnote').off('click').on('click', add_note);
+	$('.wm-note-colour').off('click').on('click', function() {
+		$('#note_colour').val($(this).attr('data-colour'));
+		wmNoteRefreshPalette();
+	});
+	$('#note_colour').off('input change').on('input change', wmNoteRefreshPalette);
+	$('#note_advanced_toggle').off('click').on('click', function() {
+		var open = $(this).attr('aria-expanded') !== 'true';
+		$(this).attr('aria-expanded', String(open)).text(open ? wmEditorText.hideAdvanced : wmEditorText.advanced);
+		$('#note_advanced').toggle(open);
+	});
+	$('#note_clone').off('click').on('click', function() {
+		$('#note_name').val('');
+		$('#note_x').val(Math.min(parseInt($('#note_x').attr('max'), 10), parseInt($('#note_x').val(), 10) + 20));
+		$('#note_y').val(Math.min(parseInt($('#note_y').attr('max'), 10), parseInt($('#note_y').val(), 10) + 20));
+		$('#note_delete,#note_move,#note_clone').hide();
+		$('#note_text').trigger('focus');
+	});
+	$('#note_move').off('click').on('click', function() {
+		$('#param').val($('#note_name').val());
+		$('#node_name').val($('#note_name').val());
+		hide_dialog('dlgNoteProperties');
+		move_node();
+	});
+	$('#note_delete').off('click').on('click', function() {
+		$('#param').val($('#note_name').val());
+		$('#node_name').val($('#note_name').val());
+		delete_node();
+	});
 	$('#tb_poslegend').off('click').on('click', position_first_legend);
 	$('#tb_postime').off('click').on('click', position_timestamp);
 	$('#tb_colours').off('click').on('click', manage_colours);
@@ -765,11 +797,12 @@ function delete_node() {
 
 	var name = $('#node_name').val();
 	var connected = Object.keys(Links).filter(function(key) { return Links[key].a === name || Links[key].b === name; }).length;
-	var message = delNodePrompt.replace('%s', function() { return wmNodeDisplayName(name); });
+	var isNote = typeof WMNotes !== 'undefined' && Object.prototype.hasOwnProperty.call(WMNotes, name);
+	var message = (isNote ? wmEditorText.noteDelete : delNodePrompt).replace('%s', function() { return wmNodeDisplayName(name); });
 	if (connected) {
 		message += ' ' + delNodeConnected.replace('%s', String(connected));
 	}
-	$('.dlgConfirm').text(message + ' ' + delNodeKeepDevice);
+	$('.dlgConfirm').text(message + (isNote ? '' : ' ' + delNodeKeepDevice));
 
 	if (['add_link', 'add_link2', 'add_node', 'place_note', 'move_node', 'via_link', 'place_legend', 'place_stamp'].indexOf($('#action').val()) !== -1) $('#action').val('');
 	mapmode('existing');
@@ -777,7 +810,7 @@ function delete_node() {
 	$('.dlgConfirm').dialog({
 		close: function() { mapmode('existing'); },
 		resizable: false,
-		title: delNodeTitle,
+		title: isNote ? wmEditorText.noteDeleteTitle : delNodeTitle,
 		height: 'auto',
 		width: 400,
 		modal: true,
@@ -790,7 +823,7 @@ function delete_node() {
 				}
 			},
 			{
-				text: txtDelNode,
+				text: isNote ? wmEditorText.noteDeleteAction : txtDelNode,
 				'class': 'wm-delete-action',
 				click: function() {
 					$(this).dialog('close');
@@ -892,6 +925,19 @@ function delete_link() {
 	});
 }
 
+function wmEditorReloadUrl() {
+	var url = new URL(window.location.href);
+	url.searchParams.set('mapname', $('#mapname').val());
+	url.searchParams.set('action', 'nothing');
+	url.searchParams.delete('config_revision');
+	url.searchParams.delete('__csrf_magic');
+	return url.href;
+}
+
+function wmReloadEditor() {
+	window.location.replace(wmEditorReloadUrl());
+}
+
 function form_submit(event) {
 	// Property dialogs can remain open while a toolbar placement action is active.
 	// Their own Save buttons always dispatch the properties they are showing.
@@ -916,34 +962,40 @@ function form_submit(event) {
 		mapmode('existing');
 	}
 
+	if ($('#action').val() === 'place_note') {
+		show_note('', $('#x').val(), $('#y').val());
+		return;
+	}
+	var noteAction = $('#action').val();
+	var noteTarget = noteAction === 'set_note_properties' ? $('#note_name').val() : noteAction === 'move_node' ? $('#node_name').val() : $('#param').val();
+	var savingNote = noteAction === 'set_note_properties' || (['move_node', 'delete_node'].indexOf(noteAction) !== -1 && typeof WMNotes !== 'undefined' && WMNotes[noteTarget]);
 	var data = $('input, select, textarea').serialize();
+	if (typeof WMConfigRevision !== 'undefined') data += '&config_revision=' + encodeURIComponent(WMConfigRevision);
 
 	$.ajax({
 		type: 'POST',
 		url: editor_url,
 		data: data,
-		success: function(html) {
+		error: function(xhr) {
+			if (xhr && xhr.status === 409) {
+				window.alert(wmEditorText.staleError);
+				return;
+			}
+			if (savingNote) {
+				if (noteAction !== 'set_note_properties') show_note(noteTarget);
+				$('#wm-note-error').text(wmEditorText.noteError).show();
+			} else {
+				window.alert(wmEditorText.saveError);
+			}
+		},
+		success: function() {
 			hide_all_dialogs();
-
-			$.get('?action=load_area_data&mapname=' + encodeURIComponent($('#mapname').val()), function(data) {
-				$('.mapData').empty().html(data);
-
-				$.getScript('?action=load_map_javascript&mapname=' + encodeURIComponent($('#mapname').val()), function(data) {
-					var date = new Date();
-
-					// Reload the images to update page
-					$('#existingdata').attr('src', $('#existingdata').attr('src') + '&date=' + date.getTime());
-					$('#xycapture').attr('src', $('#xycapture').attr('src') + '&date=' + date.getTime());
-
-					$('#action').val('');
-
-					initJS();
-				});
-			});
+			wmReloadEditor();
 		}
 	});
 }
 
+
 function map_properties() {
 	mapmode('existing');
 
@@ -1087,6 +1139,10 @@ function prime_node_form(name) {
 }
 
 function show_node(name) {
+	if (typeof WMNotes !== 'undefined' && Object.prototype.hasOwnProperty.call(WMNotes, name)) {
+		show_note(name);
+		return;
+	}
 	mapmode('existing');
 
 	hide_all_dialogs();
@@ -1298,6 +1354,7 @@ function hide_all_dialogs() {
 	hide_dialog('dlgLinkProperties');
 	hide_dialog('dlgTextEdit');
 	hide_dialog('dlgNodeProperties');
+	hide_dialog('dlgNoteProperties');
 	hide_dialog('dlgColours');
 	hide_dialog('dlgImages');
 	hide_dialog('dlgEditorSettings');
@@ -1769,3 +1826,47 @@ function wmFriendlyLinkNames() {
 function wmDecodeEditorUrl(value) {
 	return String(value || '').replace(/&/g, '&');
 }
+// Notes are ordinary label-only nodes, with a small editor-specific style form.
+function add_note() {
+	hide_all_dialogs();
+	$('#tb_help').addClass('wm-action-help').text(wmEditorText.addNoteHelp);
+	$('#action').val('place_note');
+	mapmode('xy');
+}
+function wmNoteRefreshPalette() {
+	var colour = String($('#note_colour').val()).toLowerCase();
+	$('.wm-note-colour').each(function() {
+		var selected = $(this).attr('data-colour') === colour;
+		$(this).attr('aria-pressed', selected ? 'true' : 'false').css('outline', selected ? '2px solid currentColor' : '');
+	});
+}
+function show_note(name, x, y) {
+	hide_all_dialogs();
+	mapmode('existing');
+	var node = name ? Nodes[name] : null;
+	var style = name ? WMNotes[name] : null;
+	$('#note_name').val(name);
+	$('#note_align').val(style && ['left', 'centre', 'right'].indexOf(style.align) !== -1 ? style.align : 'left');
+	$('#note_text').val(node ? (style && typeof style.text === 'string' ? style.text : node.label.replace(/\\n/g, '\n')) : '');
+	$('#note_x').val(node ? node.x : x);
+	$('#note_y').val(node ? node.y : y);
+	$('#note_colour').val(style ? style.colour : '#000000');
+	wmNoteRefreshPalette();
+	$('#note_advanced').hide();
+	$('#note_advanced_toggle').attr('aria-expanded', 'false').text(wmEditorText.advanced);
+	if (style) {
+		if (!$('#note_font option').filter(function() { return this.value === style.font; }).length) {
+			$('<option>').val(style.font).text(style.fontLabel).appendTo('#note_font');
+		}
+		$('#note_font').val(style.font);
+	} else {
+		var defaultFont = $('#note_font option').filter(function() { return this.value === 'bundled:Vera.ttf:9' || $(this).attr('data-wm-note-default') === '1'; }).first();
+		$('#note_font').val(defaultFont.length ? defaultFont.val() : '3');
+	}
+	$('#note_delete,#note_move,#note_clone').toggle(!!node);
+	$('#wm-note-error').hide();
+	$('#action').val('set_note_properties');
+	show_dialog('dlgNoteProperties');
+	$('#note_font,#note_align').each(function() { if ($(this).data('ui-selectmenu')) $(this).selectmenu('refresh'); });
+	$('#note_text').trigger('focus');
+}
diff --git a/lib/WeatherMap.class.php b/lib/WeatherMap.class.php
index b78c884..8be3076 100644
--- a/lib/WeatherMap.class.php
+++ b/lib/WeatherMap.class.php
@@ -45,6 +45,7 @@
 require_once('WeatherMap.functions.php');
 require_once('geometry.php');
 require_once('WeatherMapNode.class.php');
+require_once('WeatherMap.notes.php');
 require_once('WeatherMapLink.class.php');
 
 $weathermap_debugging  = false;
@@ -341,6 +342,9 @@ class WeatherMap extends WeatherMapBase {
 	var $colours;
 	/** @var mixed */
 	var $configfile;
+	var $config_revision = null;
+	var $config_dependencies = [];
+	var $editor_config_revision = null;
 	/** @var mixed */
 	var $imagefile;
 	/** @var mixed */
@@ -941,7 +945,8 @@ function ProcessString($input, &$context, $include_notes = true, $multiline = fa
 
 		if ($multiline == true) {
 			$i     = $input;
-			$input = str_replace('\\n', "\n", $i);
+			$input = $context instanceof WeatherMapNode && $context->get_hint('editor_note_escaped', '0') === '1'
+				? wm_note_decode_text($i) : str_replace('\\n', "\n", $i);
 		}
 
 		$output = $input;
@@ -2445,6 +2450,7 @@ function DrawTitle($image, $font, $colour) {
 	 */
 	function ReadConfig($input, $is_include = false) {
 		global $config, $weathermap_error_suppress;
+		if (!$is_include) { $this->config_revision = null; $this->config_dependencies = []; }
 
 		$curnode    = null;
 		$curlink    = null;
@@ -2474,6 +2480,8 @@ function ReadConfig($input, $is_include = false) {
 			$filename = $input;
 
 			if ($is_include) {
+				$dependencyPath = realpath($filename) ?: (realpath(dirname($filename)) ?: dirname($filename)) . '/' . basename($filename);
+				if (!array_key_exists($dependencyPath, $this->config_dependencies)) $this->config_dependencies[$dependencyPath] = null;
 				wm_debug('ReadConfig Detected that this is an INCLUDED config filename.');
 
 				if ($is_include && in_array($filename, $this->included_files, true)) {
@@ -2491,16 +2499,21 @@ function ReadConfig($input, $is_include = false) {
 			}
 
 			if (is_file($filename)) {
-				$fd = fopen($filename, 'r');
+				$fd = fopen($filename, 'rb');
 
 				if ($fd) {
+					$revision = hash_init('sha256');
 					while (($buffer = fgets($fd, 4096)) !== false) {
+						hash_update($revision, $buffer);
 						// strip out any Windows line-endings that have gotten in here
 						$buffer  = str_replace("\r", '', $buffer);
 						$lines[] = $buffer;
 					}
 
 					fclose($fd);
+					$loadedRevision = hash_final($revision);
+					if (!$is_include) $this->config_revision = $loadedRevision;
+					else $this->config_dependencies[$dependencyPath] = $loadedRevision;
 				}
 			}
 		}
@@ -3604,24 +3617,34 @@ function WriteDataFile($filename) {
 
 	/**
 	 * @param string $filename
+	 * @param bool $createOnly Require a new destination.
+	 * @param string|null $expectedRevision Optional request snapshot revision.
+	 * @param resource|null $heldLock Caller-owned destination directory mutex.
 	 * @return bool
 	 */
-	function WriteConfig($filename) {
-		$fd = false;
-
-		if (is_writable(dirname($filename)) || (file_exists($filename) && is_writable($filename))) {
-			$fd = fopen($filename, 'w');
-			assert($fd !== false);
-		}
+	function WriteConfig($filename, $createOnly = false, $expectedRevision = null, $heldLock = null) {
+		require_once __DIR__ . '/WeatherMap.config.php';
+		$fd = fopen('php://temp', 'w+b');
 
 		$output = '';
 
 		$weathermap_version = plugin_weathermap_numeric_version();
 
 		if ($fd) {
+			$write_ok = true;
+			$write = function($data) use ($fd, &$write_ok) {
+				if (!$write_ok) return;
+				$length = strlen($data);
+				$offset = 0;
+				while ($offset < $length) {
+					$count = @fwrite($fd, substr($data, $offset));
+					if ($count === false || $count === 0) { $write_ok = false; return; }
+					$offset += $count;
+				}
+			};
 			$output .= "# Automatically generated by php-weathermap v$weathermap_version\n\n";
 
-			if (count($this->fonts) > 0) {
+			if (cacti_count($this->fonts) > 0) {
 				foreach ($this->fonts as $fontnumber => $font) {
 					if ($font->type == 'truetype') {
 						$output .= sprintf("FONTDEFINE %d %s %d\n", $fontnumber, $font->file, $font->size);
@@ -3723,19 +3746,19 @@ function WriteConfig($filename) {
 
 				$locale = localeconv();
 
-				$decimal_point = $locale['decimal_point'];
+				$decimal_point = '.';
 
 				foreach ($colours as $k => $colour) {
 					if (!isset($colour['special']) || !$colour['special']) {
-						$top    = rtrim(rtrim(sprintf('%f', $colour['top']), '0'), $decimal_point);
-						$bottom = rtrim(rtrim(sprintf('%f', $colour['bottom']), '0'), $decimal_point);
+						$top    = rtrim(rtrim(sprintf('%F', $colour['top']), '0'), $decimal_point);
+						$bottom = rtrim(rtrim(sprintf('%F', $colour['bottom']), '0'), $decimal_point);
 
 						if ($bottom > 1000) {
-							$bottom = nice_bandwidth($colour['bottom'], $this->kilo);
+							$bottom = str_replace(localeconv()['decimal_point'], '.', nice_bandwidth($colour['bottom'], $this->kilo));
 						}
 
 						if ($top > 1000) {
-							$top = nice_bandwidth($colour['top'], $this->kilo);
+							$top = str_replace(localeconv()['decimal_point'], '.', nice_bandwidth($colour['top'], $this->kilo));
 						}
 
 						$tag = ($colour['tag'] ?? '');
@@ -3782,18 +3805,18 @@ function WriteConfig($filename) {
 
 			$output .= "\n# End of global section\n\n";
 
-			fwrite($fd, $output);
+			$write($output);
 
 			// # fwrite($fd,$this->nodes['DEFAULT']->WriteConfig());
 			// # fwrite($fd,$this->links['DEFAULT']->WriteConfig());
 
-			// fwrite($fd, "\n\n# Node definitions:\n");
+			// $write("\n\n# Node definitions:\n");
 
 			foreach (['template', 'normal'] as $which) {
 				if ($which == 'template') {
-					fwrite($fd, "\n# TEMPLATE-only NODEs:\n");
+					$write("\n# TEMPLATE-only NODEs:\n");
 				} elseif ($which == 'normal') {
-					fwrite($fd, "\n# regular NODEs:\n");
+					$write("\n# regular NODEs:\n");
 				}
 
 				foreach ($this->nodes as $node_name => $node) {
@@ -3801,21 +3824,21 @@ function WriteConfig($filename) {
 						if ($node->defined_in == $this->configfile || $node_name == 'DEFAULT') {
 							if ($which == 'template' && $node_name == 'DEFAULT') {
 								wm_debug('TEMPLATE Node DEFAULT');
-								fwrite($fd, $node->WriteConfig());
+								$write($node->WriteConfig());
 							} elseif ($which == 'template' && $node->x === null) {
 								wm_debug('TEMPLATE Node NON-DEFAULT');
-								fwrite($fd, $node->WriteConfig());
+								$write($node->WriteConfig());
 							} elseif ($which == 'normal' && $node->x !== null) {
-								fwrite($fd, $node->WriteConfig());
+								$write($node->WriteConfig());
 							}
 						}
 					}
 				}
 
 				if ($which == 'template') {
-					fwrite($fd, "\n# TEMPLATE-only LINKs:\n");
+					$write("\n# TEMPLATE-only LINKs:\n");
 				} elseif ($which == 'normal') {
-					fwrite($fd, "\n# regular LINKs:\n");
+					$write("\n# regular LINKs:\n");
 				}
 
 				foreach ($this->links as $link_name => $link) {
@@ -3823,22 +3846,27 @@ function WriteConfig($filename) {
 						if ($link->defined_in == $this->configfile || $link_name == 'DEFAULT') {
 							if ($which == 'template' && $link_name == 'DEFAULT') {
 								wm_debug('TEMPLATE Link DEFAULT');
-								fwrite($fd, $link->WriteConfig());
+								$write($link->WriteConfig());
 							} elseif ($which == 'template' && $link->a === null) {
 								wm_debug('TEMPLATE Link NON-DEFAULT');
-								fwrite($fd, $link->WriteConfig());
+								$write($link->WriteConfig());
 							} elseif ($which == 'normal' && $link->a !== null) {
-								fwrite($fd, $link->WriteConfig());
+								$write($link->WriteConfig());
 							}
 						}
 					}
 				}
 			}
 
-			fwrite($fd, "\n\n# That's All Folks!\n");
-			fclose($fd);
+			$write("\n\n# That's All Folks!\n");
+			rewind($fd);
+			$contents = stream_get_contents($fd);
+			$closed = fclose($fd);
 
-			return (true);
+			$sameFile = $this->configfile !== '' && $filename === $this->configfile;
+			$saved = $write_ok && $contents !== false && $closed && \WeathermapConfig\atomicWrite($filename, $contents, $sameFile, $expectedRevision ?? ($sameFile ? $this->config_revision : null), $createOnly, $heldLock, $this->config_dependencies);
+			if ($saved && $sameFile) $this->config_revision = hash('sha256', $contents);
+			return $saved;
 		} else {
 			wm_warn("Couldn't open config file $filename for writing");
 
@@ -4005,6 +4033,11 @@ function DrawMap($filename = '', $thumbnailfile = '', $thumbnailmax = 250, $with
 
 			// do the node rendering stuff first, regardless of where they are actually drawn.
 			// this is so we can get the size of the nodes, which links will need if they use offsets
+			foreach ($this->nodes as $node) {
+				$node->render_note_hidpi = false;
+				if ($node->get_hint('editor_note', '0') === '1') $node->labelfont = wm_note_font_id($this, $node->labelfont);
+			}
+
 			foreach ($this->nodes as $node) {
 				// don't try and draw template nodes
 				wm_debug('Pre-rendering ' . $node->name . ' to get bounding boxes.');
@@ -4014,6 +4047,17 @@ function DrawMap($filename = '', $thumbnailfile = '', $thumbnailmax = 250, $with
 				}
 			}
 
+			$sharpNotes = ($filename !== 'null' && $withnodes && $this->context !== 'editor2') ? wm_sharp_notes($this) : [];
+			$noteImages = $sharpNotes !== [] ? wm_note_prepare_images($this) : false;
+			if ($noteImages === false) $sharpNotes = [];
+			foreach ($sharpNotes as $node) {
+				$node->render_note_hidpi = true;
+				$bounds = $node->boundingboxes;
+				$node->pre_render($image, $this);
+				$node->boundingboxes = $bounds;
+			}
+
+			$noteForeground = null;
 			$all_layers = array_keys($this->seen_zlayers);
 			sort($all_layers);
 
@@ -4024,6 +4068,15 @@ function DrawMap($filename = '', $thumbnailfile = '', $thumbnailmax = 250, $with
 
 				// all the map 'furniture' is fixed at z=1000
 				if ($z == 1000) {
+					if ($sharpNotes !== []) {
+						$baseImage = $image;
+						$image = $noteImages[1];
+						imagesavealpha($image, true);
+						imagealphablending($image, false);
+						imagefill($image, 0, 0, imagecolorallocatealpha($image, 0, 0, 0, 127));
+						imagealphablending($image, true);
+						$noteForeground = $image;
+					}
 					foreach ($this->colours as $scalename => $colours) {
 						wm_debug("Drawing KEY for $scalename if necessary.");
 
@@ -4060,6 +4113,7 @@ function DrawMap($filename = '', $thumbnailfile = '', $thumbnailmax = 250, $with
 					$this->DrawTitle($image, $this->titlefont, $this->colours['DEFAULT']['TITLE']['gdref1']);
 				}
 
+
 				if (is_array($z_items)) {
 					foreach ($z_items as $it) {
 						if (strtolower((string) get_class($it)) == 'weathermaplink') {
@@ -4144,6 +4198,22 @@ function DrawMap($filename = '', $thumbnailfile = '', $thumbnailmax = 250, $with
 			//	$this->myimagestring($image, 30, 100, 100, "Test 1\nLine 2", $overlay,0);
 			// $this->myimagestring($image, 30, 200, 200, "Test 1\nLine 2", $overlay,45);
 
+			// Compose at logical coordinates; render note glyphs at display density.
+			if ($sharpNotes !== []) {
+				if ($noteForeground !== null) $image = $baseImage;
+				$this->image = $image;
+				$image = wm_note_display_image($this, $sharpNotes, $noteImages[0]);
+				if ($noteForeground !== null) {
+					imagecopyresampled($image, $noteForeground, 0, 0, 0, 0, imagesx($image), imagesy($image), $this->width, $this->height);
+					imagedestroy($noteForeground);
+				}
+				$this->image = $image;
+			}
+			foreach ($this->nodes as $node) {
+				$node->render_note_hidpi = false;
+				if ($node->get_hint('editor_note', '0') === '1') $node->labelfont = wm_note_font_id($this, $node->labelfont);
+			}
+
 			// Ready to output the results...
 
 			if ($filename == 'null') {
@@ -4209,7 +4279,7 @@ function DrawMap($filename = '', $thumbnailfile = '', $thumbnailmax = 250, $with
 					$imagethumb = imagecreatetruecolor(max(1, $this->thumb_width), max(1, $this->thumb_height));
 
 					imagecopyresampled($imagethumb, $image, 0, 0, 0, 0, $this->thumb_width, $this->thumb_height,
-						(int) round((float) $this->width), (int) round((float) $this->height)
+						imagesx($image), imagesy($image)
 					);
 
 					$result = imagepng($imagethumb, $thumbnailfile);
diff --git a/lib/WeatherMap.config.php b/lib/WeatherMap.config.php
new file mode 100644
index 0000000..9a0fa86
--- /dev/null
+++ b/lib/WeatherMap.config.php
@@ -0,0 +1,171 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+
+namespace WeathermapConfig;
+
+/**
+ * Acquire a persistent directory lock shared by config writers and deletion.
+ *
+ * @param string|null $directory Destination directory; null selects plugin configs.
+ * @param bool $blocking Wait for the lock, or return false when it is busy.
+ *
+ * @return resource|false The exclusive lock handle, or false on failure.
+ */
+function acquire($directory = null, $blocking = true) {
+	$directory = realpath($directory ?? dirname(__DIR__) . '/configs');
+	if ($directory === false) return false;
+	$path = $directory . '/.weathermap-config.lock';
+	if (!is_writable($directory) && !file_exists($path) && !is_link($path)) return false;
+	$handle = @fopen($path, 'c+b');
+	if (!$handle) $handle = @fopen($path, 'rb');
+	if ($handle && flock($handle, LOCK_EX | ($blocking ? 0 : LOCK_NB))) return $handle;
+	if ($handle) fclose($handle);
+	return false;
+}
+
+/**
+ * Release a configuration lock.
+ *
+ * @param resource $handle The acquired lock.
+ *
+ * @return void
+ */
+function release($handle) {
+	flock($handle, LOCK_UN);
+	fclose($handle);
+}
+
+/**
+ * Write all bytes, including when the stream accepts only a partial chunk.
+ *
+ * @param resource $stream The writable stream.
+ * @param string $contents The bytes to write.
+ *
+ * @return bool Whether every byte was written.
+ */
+function writeAll($stream, $contents) {
+	$offset = 0;
+	$length = strlen($contents);
+	while ($offset < $length) {
+		$written = @fwrite($stream, substr($contents, $offset));
+		if ($written === false || $written === 0) return false;
+		$offset += $written;
+	}
+	return true;
+}
+
+/**
+ * Compare every included configuration against the bytes used by the snapshot.
+ * @param array<string,string> $dependencies Included filenames and hashes.
+ * @return bool Whether all dependencies still match.
+ */
+function dependenciesMatch($dependencies) {
+	foreach ($dependencies as $path => $revision) {
+		clearstatcache(true, $path);
+		if (!is_string($revision) || @hash_file('sha256', $path) !== $revision) return false;
+	}
+	return true;
+}
+
+/**
+ * Bind an editor token to its root configuration and included dependencies.
+ * @param string|null $root Root configuration hash.
+ * @param array<string,string> $dependencies Included filenames and hashes.
+ * @return string|null Snapshot token.
+ */
+function snapshotRevision($root, $dependencies) {
+	if (!$dependencies) return $root;
+	ksort($dependencies);
+	return hash('sha256', serialize([$root, $dependencies]));
+}
+
+/**
+ * Replace a configuration only after a complete, flushed and closed local write.
+ *
+ * @param string $filename The destination configuration path.
+ * @param string $contents The complete new configuration.
+ * @param bool $mustExist Refuse to recreate an existing map deleted during editing.
+ * @param string|null $expectedRevision SHA-256 of the snapshot being edited.
+ * @param bool $createOnly Refuse to replace an existing destination.
+ * @param resource|null $heldLock Optional caller-owned mutex for this destination directory.
+ *
+ * @param array<string,string> $dependencies Included configuration snapshots.
+ * @param callable|null $validate Additional commit-time validation.
+ * @return bool Success; failures preserve the existing configuration.
+ */
+function atomicWrite($filename, $contents, $mustExist = false, $expectedRevision = null, $createOnly = false, $heldLock = null, $dependencies = [], $validate = null) {
+	if (strpos($filename, '://') !== false) return false;
+	$lockDirectory = dirname($filename);
+	if (is_link($filename)) $filename = realpath($filename);
+	if ($filename === false || !is_dir(dirname($filename)) || !is_writable(dirname($filename))) return false;
+	if (file_exists($filename) && (!is_file($filename) || !is_writable($filename))) return false;
+	$existed = file_exists($filename);
+	$mustExist = $mustExist || $existed;
+	$ownsLock = $heldLock === null;
+	$lockPath = realpath($lockDirectory . '/.weathermap-config.lock');
+	if (!$ownsLock && ($lockPath === false || !is_resource($heldLock) || get_resource_type($heldLock) !== 'stream' || realpath(stream_get_meta_data($heldLock)['uri']) !== $lockPath)) return false;
+	$lock = $ownsLock ? acquire($lockDirectory) : $heldLock;
+	if (!$lock) return false;
+	$temp = false;
+	$stream = false;
+	$dependencyLocks = [];
+	try {
+		clearstatcache(true, $filename);
+		if (($createOnly || !$existed) && file_exists($filename)) return false;
+		if ($mustExist && !is_file($filename)) return false;
+		if (file_exists($filename) && (!is_file($filename) || !is_writable($filename))) return false;
+		// Additional directories use nonblocking locks so opposing include graphs cannot deadlock.
+		$directories = array_unique(array_merge([dirname($filename)], array_map('dirname', array_keys($dependencies))));
+		sort($directories);
+		foreach ($directories as $directory) {
+			if (realpath($directory) === realpath($lockDirectory)) continue;
+			$dependencyLock = acquire($directory, false);
+			if (!$dependencyLock) {
+				if (!is_writable($directory) && !file_exists($directory . '/.weathermap-config.lock')) continue;
+				return false;
+			}
+			$dependencyLocks[] = $dependencyLock;
+		}
+		if ($expectedRevision !== null && @hash_file('sha256', $filename) !== $expectedRevision) return false;
+		if (!dependenciesMatch($dependencies) || ($validate !== null && !$validate())) return false;
+
+		$temp = @tempnam(dirname($filename), '.wm-config-');
+		if ($temp === false) return false;
+		$stream = @fopen($temp, 'wb');
+		if (!$stream) return false;
+		$complete = writeAll($stream, $contents) && fflush($stream);
+		$closed = fclose($stream);
+		$stream = false;
+		if (!$complete || !$closed) return false;
+		$mode = file_exists($filename) ? fileperms($filename) & 0777 : 0666 & ~umask();
+		if (PHP_OS_FAMILY !== 'Windows' && file_exists($filename) && !chgrp($temp, filegroup($filename))) return false;
+		if (!chmod($temp, $mode)) return false;
+		return @rename($temp, $filename);
+	} finally {
+		if (is_resource($stream)) fclose($stream);
+		if ($temp !== false && file_exists($temp)) unlink($temp);
+		foreach ($dependencyLocks as $dependencyLock) release($dependencyLock);
+		if ($ownsLock) release($lock);
+	}
+}
diff --git a/lib/WeatherMap.notes.php b/lib/WeatherMap.notes.php
new file mode 100644
index 0000000..1bb01ab
--- /dev/null
+++ b/lib/WeatherMap.notes.php
@@ -0,0 +1,182 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+
+namespace WeathermapNotes {
+	/**
+	 * Allocate a note canvas without propagating GD allocation failures.
+	 *
+	 * @param int $width Canvas width.
+	 * @param int $height Canvas height.
+	 * @return \GdImage|false Allocated canvas, or false when unavailable.
+	 */
+	function allocate($width, $height) {
+		try {
+			return @imagecreatetruecolor($width, $height);
+		} catch (\Throwable $error) {
+			return false;
+		}
+	}
+}
+
+namespace {
+/**
+ * Decode text from an escaped note label, preserving literal backslashes.
+ *
+ * @param string $text Encoded configuration label.
+ * @return string Display text.
+ */
+function wm_note_decode_text($text) {
+	return preg_replace_callback('/\\\\(\\\\|n)/', function ($match) {
+		return $match[1] === 'n' ? "\n" : '\\';
+	}, $text);
+}
+
+/**
+ * Resolve a usable note font before measuring or drawing its text.
+ *
+ * @param WeatherMap $map The rendered map.
+ * @param int|string $id Registered font slot.
+ * @return int|string Usable font slot, or built-in font 3.
+ */
+function wm_note_font_id($map, $id) {
+	if (!isset($map->fonts[$id])) return 3;
+	$font = $map->fonts[$id];
+	if ($font->type === 'truetype') {
+		$file = wm_font_file($font->file);
+		if (!is_readable($file) || !function_exists('imagettfbbox') || !function_exists('imagettftext')) return 3;
+		$signature = @file_get_contents($file, false, null, 0, 4);
+		if (!in_array($signature, ["\x00\x01\x00\x00", 'OTTO', 'ttcf', 'true', 'typ1'], true)) return 3;
+		set_error_handler(function () { return true; }, E_WARNING);
+		try { $bounds = imagettfbbox($font->size, 0, $file, 'Wm'); } catch (Throwable $error) { return 3; } finally { restore_error_handler(); }
+		if (!is_array($bounds) || count($bounds) !== 8) return 3;
+	}
+	return $id;
+}
+
+/**
+ * Notes eligible for high-density map rendering. Restrict the allocation to
+ * bounded maps and plain TrueType annotations drawn above the other objects.
+ *
+ * @param WeatherMap $map The rendered map and its object layers.
+ * @return WeatherMapNode[] Notes eligible for high-density rendering.
+ */
+function wm_sharp_notes($map) {
+	if ($map->width < 1 || $map->height < 1 || $map->width * $map->height > 4000000) {
+		return [];
+	}
+	$notes = [];
+	$layers = $map->seen_zlayers;
+	ksort($layers, SORT_NUMERIC);
+	// Follow draw order; later nodes only block annotations they overlap.
+	foreach ($layers as $items) {
+		foreach ($items ?? [] as $node) {
+			if ($node instanceof WeatherMapNode && $node->name !== 'DEFAULT' && $node->get_hint('editor_note', '0') === '1' && $node->labelangle == 0 && $node->iconfile === '' && $node->zorder < 1000 && $node->labelbgcolour == [-1,-1,-1] && $node->labeloutlinecolour == [-1,-1,-1] && $node->labelfontshadowcolour == [-1,-1,-1] && isset($map->fonts[$node->labelfont]) && $map->fonts[$node->labelfont]->type === 'truetype') {
+				$notes[] = $node;
+			} elseif ($node instanceof WeatherMapNode && !is_null($node->x)) {
+				$notes = array_values(array_filter($notes, function ($note) use ($node) {
+					if (!$node->image || !$note->image) return false;
+					$x = (int)($node->x - $node->centre_x);
+					$y = (int)($node->y - $node->centre_y);
+					$nx = (int)($note->x - $note->centre_x);
+					$ny = (int)($note->y - $note->centre_y);
+					return $x >= $nx + imagesx($note->image) || $nx >= $x + imagesx($node->image)
+						|| $y >= $ny + imagesy($note->image) || $ny >= $y + imagesy($node->image);
+				}));
+			} elseif (!($node instanceof WeatherMapNode) || !is_null($node->x)) {
+				$notes = [];
+			}
+		}
+	}
+	return $notes;
+}
+
+/**
+ * Reserve both note canvases before suppressing logical-resolution glyphs.
+ *
+ * @param WeatherMap $map Map being rendered.
+ * @return array{GdImage, GdImage}|false Display and foreground canvases.
+ */
+function wm_note_prepare_images($map) {
+	$display = \WeathermapNotes\allocate($map->width * 2, $map->height * 2);
+	if ($display === false) return false;
+	$foreground = \WeathermapNotes\allocate($map->width, $map->height);
+	if ($foreground === false) {
+		imagedestroy($display);
+		return false;
+	}
+	return [$display, $foreground];
+}
+
+/**
+ * Render glyphs at twice the density; do not enlarge an existing text bitmap.
+ *
+ * @param WeatherMap $map The composed logical-resolution map.
+ * @param WeatherMapNode[] $notes Notes to draw over the composed image.
+ * @param GdImage|null $image Optional preallocated display canvas.
+ * @return GdImage|false The display image, or false on allocation failure.
+ */
+function wm_note_display_image($map, $notes, $image = null) {
+	$image = $image ?? \WeathermapNotes\allocate($map->width * 2, $map->height * 2);
+	if ($image === false) return false;
+	imagecopyresampled($image, $map->image, 0, 0, 0, 0, $map->width * 2, $map->height * 2, $map->width, $map->height);
+	foreach ($notes as $node) {
+		$lines = explode("\n", $node->proclabel);
+		$width = 0;
+		foreach ($lines as $line) {
+			[$lineWidth] = $map->myimagestringsize($node->labelfont, $line);
+			$width = max($width, $lineWidth);
+		}
+		[, $height] = $map->myimagestringsize($node->labelfont, 'Ag');
+		$height = max(1, ceil($height));
+		$font = $map->fonts[$node->labelfont];
+		$colour = imagecolorallocate($image, ...$node->labelfontcolour);
+		$originX = (int)($node->x - $node->centre_x);
+		$originY = (int)($node->y - $node->centre_y);
+		$lineY = $node->centre_y - cacti_count($lines) * $height / 2 + $height;
+		foreach ($lines as $line) {
+			[$lineWidth] = $map->myimagestringsize($node->labelfont, $line);
+			$align = $node->get_hint('editor_note_align', 'left');
+			$offset = $align === 'right' ? $width - $lineWidth : ($align === 'centre' ? ($width - $lineWidth) / 2 : 0);
+			$x = $originX + round($node->centre_x - $width / 2 + $offset);
+			$y = $originY + round($lineY);
+			wimagettftext($image, $font->size * 2, 0, $x * 2, $y * 2, $colour, wm_font_file($font->file), $line);
+			$lineY += $height;
+		}
+	}
+	return $image;
+}
+
+/**
+ * Size the live-view bitmap in logical map coordinates, including high-density output.
+ *
+ * @param WeatherMap $map The map supplying logical display dimensions.
+ * @param string|int $id The registered map identifier.
+ * @return string Escaped live-view image markup.
+ */
+function wm_liveview_image_html($map, $id) {
+	$url = htmlspecialchars('?action=liveviewimage&id=' . rawurlencode((string)$id), ENT_QUOTES, 'UTF-8');
+	return '<img src="' . $url . '" width="' . (int)$map->width . '" height="' . (int)$map->height . '" />' . "\n";
+}
+
+}
diff --git a/lib/WeatherMapNode.class.php b/lib/WeatherMapNode.class.php
index 7abcef8..75fa240 100644
--- a/lib/WeatherMapNode.class.php
+++ b/lib/WeatherMapNode.class.php
@@ -168,6 +168,7 @@ class WeatherMapNode extends WeatherMapItem {
 	var $relative_to;
 	/** @var mixed */
 	var $zorder;
+	var $render_note_hidpi = false;
 	/** @var mixed */
 	var $template;
 	/** @var mixed */
@@ -357,6 +358,18 @@ function pre_render($image, &$map) {
 			}
 
 			[$strwidth, $strheight] = $map->myimagestringsize($this->labelfont, $this->proclabel);
+			$noteLines = null;
+			if ($this->get_hint('editor_note', '0') === '1' && $this->labelangle == 0) {
+				$noteLines = explode("\n", $this->proclabel);
+				$strwidth = 0;
+				foreach ($noteLines as $line) {
+					[$lineWidth] = $map->myimagestringsize($this->labelfont, $line);
+					$strwidth = max($strwidth, $lineWidth);
+				}
+				[, $noteLineHeight] = $map->myimagestringsize($this->labelfont, 'Ag');
+				$noteLineHeight = max(1, ceil($noteLineHeight));
+				$strheight = cacti_count($noteLines) * $noteLineHeight;
+			}
 
 			if ($this->labelangle == 90 || $this->labelangle == 270) {
 				$boxwidth  = ($strheight * $padfactor) + $padding;
@@ -775,7 +788,20 @@ function pre_render($image, &$map) {
 				}
 			}
 
-			$map->myimagestring($node_im, $this->labelfont, $txt_x, $txt_y, $this->proclabel, $txcol->gdallocate($node_im),$this->labelangle);
+			if ($noteLines !== null && $this->render_note_hidpi && isset($map->fonts[$this->labelfont]) && $map->fonts[$this->labelfont]->type === 'truetype') {
+				// The editor draws this text at display resolution after composing the map.
+			} elseif ($noteLines !== null) {
+				$lineY = $txt_y - $strheight + $noteLineHeight;
+				foreach ($noteLines as $line) {
+					[$lineWidth] = $map->myimagestringsize($this->labelfont, $line);
+					$alignment = $this->get_hint('editor_note_align', 'left');
+					$lineX = $txt_x + ($alignment === 'right' ? $strwidth - $lineWidth : ($alignment === 'centre' ? ($strwidth - $lineWidth) / 2 : 0));
+					$map->myimagestring($node_im, $this->labelfont, (int)round($lineX), $lineY, $line, $txcol->gdallocate($node_im));
+					$lineY += $noteLineHeight;
+				}
+			} else {
+				$map->myimagestring($node_im, $this->labelfont, $txt_x, $txt_y, $this->proclabel, $txcol->gdallocate($node_im),$this->labelangle);
+			}
 			// $map->myimagestring($node_im, $this->labelfont, $txt_x, $txt_y, $this->proclabel, $txcol->gdallocate($node_im),90);
 		}
 
diff --git a/lib/editor.actions.php b/lib/editor.actions.php
index 8117a40..5b5ceb4 100644
--- a/lib/editor.actions.php
+++ b/lib/editor.actions.php
@@ -40,6 +40,8 @@
  +-------------------------------------------------------------------------+
 */
 
+require_once __DIR__ . '/WeatherMap.config.php';
+
 /** editor.actions.php
  *
  * All the functions used by the that wrap in request variables
@@ -49,7 +51,54 @@
  */
 
 /**
- * @return void
+ * Read an existing editor map and reject stale or unreadable targets.
+ *
+ * @param WeatherMap $map Engine receiving the configuration.
+ * @param string $mapfile Configuration path.
+ * @return bool Whether the map was loaded.
+ */
+function wm_editor_read_config($map, $mapfile) {
+	if (!is_file($mapfile) || !is_readable($mapfile)) {
+		http_response_code(404);
+		return false;
+	}
+	if (!$map->ReadConfig($mapfile)) {
+		http_response_code(422);
+		return false;
+	}
+	if (!is_string($map->config_revision)) {
+		http_response_code(404);
+		return false;
+	}
+	$revision = get_nfilter_request_var('config_revision');
+	if ($revision !== null && $revision !== '' && (!is_string($revision) || !hash_equals(\WeathermapConfig\snapshotRevision($map->config_revision, $map->config_dependencies), $revision))) {
+		http_response_code(409);
+		return false;
+	}
+	$map->editor_config_revision = $map->config_revision;
+	return true;
+}
+
+/**
+ * Propagate failed editor configuration saves to the AJAX caller.
+ *
+ * @param WeatherMap $map Engine containing the edited configuration.
+ * @param string $mapfile Configuration path.
+ * @param bool $createOnly Require a new destination for map creation.
+ * @return bool Whether the complete configuration was saved.
+ */
+function wm_editor_write_config($map, $mapfile, $createOnly = false) {
+	if (!$map->WriteConfig($mapfile, $createOnly, $map->editor_config_revision)) {
+		$current = is_file($mapfile) ? @hash_file('sha256', $mapfile) : false;
+		$stale = !\WeathermapConfig\dependenciesMatch($map->config_dependencies) || $map->editor_config_revision !== null && $current !== false && $current !== $map->editor_config_revision;
+		http_response_code($stale ? 409 : 500);
+		return false;
+	}
+	return true;
+}
+
+/**
+ * @return bool
  * @param  mixed $mapfile
  */
 function newMap($mapfile) {
@@ -59,12 +108,12 @@ function newMap($mapfile) {
 
 	require_once __DIR__ . '/editor.new-map-preset.php';
 	wm_new_map_preset($map);
-	$map->WriteConfig($mapfile);
+	return wm_editor_write_config($map, $mapfile, true);
 }
 
 /**
  * @param  mixed $mapfile
- * @return void
+ * @return bool
  */
 function newMapCopy($mapfile) {
 	global $mapdir;
@@ -85,24 +134,32 @@ function newMapCopy($mapfile) {
 		$sourcemap = $mapdir . '/' . $sourcemapname;
 
 		if (file_exists($sourcemap) && is_readable($sourcemap)) {
-			$map->ReadConfig($sourcemap);
-			$map->WriteConfig($mapfile);
+			if (!$map->ReadConfig($sourcemap) || !is_string($map->config_revision)) {
+				http_response_code(404);
+				return false;
+			}
+			return wm_editor_write_config($map, $mapfile, true);
 		}
 	}
+	http_response_code(404);
+	return false;
 }
 
 /**
- * @param  mixed $mapfile
+ * @param mixed $mapfile Configuration path.
+ * @param WeatherMap|null $map Loaded control snapshot, or null for a standalone response.
  * @return void
  */
-function getMapJavaScript($mapfile) {
-	$map = new WeatherMap;
-
-	$map->context = 'editor';
-
-	$map->ReadConfig($mapfile);
+function getMapJavaScript($mapfile, $map = null) {
+	if ($map === null) {
+		$map = new WeatherMap;
+		$map->context = 'editor';
+		if (!wm_editor_read_config($map, $mapfile)) return;
+	}
 
 	print $map->asJS();
+	print 'var WMConfigRevision = ' . json_encode(\WeathermapConfig\snapshotRevision($map->config_revision, $map->config_dependencies)) . ';';
+	print 'var WMNotes = ' . json_encode(wm_editor_note_data($map), JSON_HEX_TAG | JSON_HEX_AMP | JSON_HEX_APOS | JSON_HEX_QUOT) . ';';
 }
 
 /**
@@ -114,7 +171,7 @@ function getMapAreaData($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	// we need to draw and throw away a map, to get the
 	// dimensions for the imagemap.
@@ -141,7 +198,7 @@ function drawMap($mapfile, $selected, $use_overlay, $use_relative_overlay) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	if ($selected != '') {
 		if (substr($selected, 0, 5) == 'NODE:') {
@@ -186,7 +243,7 @@ function fetchConfig($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	header('Content-type: text/plain');
 
@@ -223,7 +280,7 @@ function setNodeConfig($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$node_name   = get_nfilter_request_var('node_name');
 	$node_config = get_nfilter_request_var('item_configtext');
@@ -231,17 +288,7 @@ function setNodeConfig($mapfile) {
 	if (isset($map->nodes[$node_name])) {
 		$map->nodes[$node_name]->config_override = $node_config;
 
-		$map->WriteConfig($mapfile);
-
-		// now clear and reload the map object, because the in-memory one is out of sync
-		// - we don't know what changes the user made here, so we just have to reload.
-		unset($map);
-
-		$map = new WeatherMap;
-
-		$map->context = 'editor';
-
-		$map->ReadConfig($mapfile);
+		if (!wm_editor_write_config($map, $mapfile)) return;
 	}
 }
 
@@ -254,7 +301,7 @@ function setLinkConfig($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$link_name   = get_nfilter_request_var('link_name');
 	$link_config = get_nfilter_request_var('item_configtext');
@@ -262,17 +309,7 @@ function setLinkConfig($mapfile) {
 	if (isset($map->links[$link_name])) {
 		$map->links[$link_name]->config_override = $link_config;
 
-		$map->WriteConfig($mapfile);
-
-		// now clear and reload the map object, because the in-memory one is out of sync
-		// - we don't know what changes the user made here, so we just have to reload.
-		unset($map);
-
-		$map = new WeatherMap;
-
-		$map->context = 'editor';
-
-		$map->ReadConfig($mapfile);
+		if (!wm_editor_write_config($map, $mapfile)) return;
 	}
 }
 
@@ -285,7 +322,7 @@ function setNodeProperties($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$node_name     = get_nfilter_request_var('node_name');
 	$new_node_name = get_nfilter_request_var('node_new_name');
@@ -362,7 +399,7 @@ function setNodeProperties($mapfile) {
 		$map->nodes[$new_node_name]->iconfile = $iconfile;
 	}
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -374,7 +411,7 @@ function setLinkProperties($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$link_name = get_nfilter_request_var('link_name');
 
@@ -442,7 +479,7 @@ function setLinkProperties($mapfile) {
 
 		// $map->links[$link_name]->SetBandwidth($bwin,$bwout);
 
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -455,7 +492,7 @@ function setMapProperties($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$map->title              = wm_editor_sanitize_string(get_nfilter_request_var('map_title'));
 	$map->keytext['DEFAULT'] = wm_editor_sanitize_string(get_nfilter_request_var('map_legend'));
@@ -479,10 +516,6 @@ function setMapProperties($mapfile) {
 		$map->add_hint('background_sizing', $background_sizing);
 	}
 
-	db_execute_prepared('UPDATE weathermap_maps
-		SET titlecache = ?
-		WHERE configfile = ?',
-		[$map->title, basename($mapfile)]);
 
 	$inheritables = [
 		['link', 'width', 'map_linkdefaultwidth', 'float']
@@ -528,7 +561,11 @@ function setMapProperties($mapfile) {
 		}
 	}
 
-	$map->WriteConfig($mapfile);
+	if (!wm_editor_write_config($map, $mapfile)) return;
+	db_execute_prepared('UPDATE weathermap_maps
+		SET titlecache = ?
+		WHERE configfile = ?',
+		[$map->title, basename($mapfile)]);
 }
 
 /**
@@ -540,7 +577,7 @@ function setMapStyle($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	if (wm_editor_validate_one_of(get_nfilter_request_var('mapstyle_htmlstyle'), ['static', 'overlib'], false)) {
 		$map->htmlstyle = strtolower(get_nfilter_request_var('mapstyle_htmlstyle'));
@@ -565,7 +602,7 @@ function setMapStyle($mapfile) {
 	wm_comment_update_default($map, 'bwfont', wm_comment_resolve_font($map, get_nfilter_request_var('mapstyle_linkfont')));
 	wm_comment_apply_style($map, get_nfilter_request_var('mapstyle_commentfont'), get_nfilter_request_var('mapstyle_commentcolour'));
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -577,7 +614,7 @@ function addLink($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$a = get_nfilter_request_var('param');
 	$b = get_nfilter_request_var('param2');
@@ -609,7 +646,7 @@ function addLink($mapfile) {
 		$map->links[$newlinkname] = $newlink;
 		array_push($map->seen_zlayers[$newlink->zorder], $newlink);
 
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -628,12 +665,12 @@ function placeLegend($mapfile, $grid_snap_value) {
 
 	$scalename = wm_editor_sanitize_name(get_nfilter_request_var('param'));
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$map->keyx[$scalename] = $x;
 	$map->keyy[$scalename] = $y;
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -649,12 +686,12 @@ function placeStamp($mapfile, $grid_snap_value) {
 	$x = snap(intval(get_nfilter_request_var('x')), $grid_snap_value);
 	$y = snap(intval(get_nfilter_request_var('y')), $grid_snap_value);
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$map->timex = $x;
 	$map->timey = $y;
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -671,11 +708,11 @@ function viaLink($mapfile) {
 
 	$link_name = wm_editor_sanitize_name(get_nfilter_request_var('link_name'));
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	if (isset($map->links[$link_name])) {
 		$map->links[$link_name]->vialist = [[0 =>$x, 1=>$y]];
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -694,8 +731,12 @@ function moveNode($mapfile, $grid_snap_value) {
 
 	$node_name = wm_editor_sanitize_name(get_nfilter_request_var('node_name'));
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
+	if (!isset($map->nodes[$node_name])) {
+		http_response_code(404);
+		return;
+	}
 	if (isset($map->nodes[$node_name])) {
 		// This is a complicated bit. Find out if this node is involved in any
 		// links that have VIAs. If it is, we want to rotate those VIA points
@@ -788,7 +829,7 @@ function moveNode($mapfile, $grid_snap_value) {
 		$map->nodes[$node_name]->x = $x;
 		$map->nodes[$node_name]->y = $y;
 
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -801,7 +842,7 @@ function linkTidy($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$target = wm_editor_sanitize_name(get_nfilter_request_var('param'));
 
@@ -811,7 +852,7 @@ function linkTidy($mapfile) {
 
 		tidy_link($map, $target);
 
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -824,13 +865,13 @@ function reTidy($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	// draw a map and throw it away, to calculate all the bounding boxes
 	$map->DrawMap('null');
 	retidy_links($map);
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -842,13 +883,13 @@ function reTidyAll($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	// draw a map and throw it away, to calculate all the bounding boxes
 	$map->DrawMap('null');
 	retidy_links($map,true);
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -860,13 +901,13 @@ function unTidy($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	// draw a map and throw it away, to calculate all the bounding boxes
 	$map->DrawMap('null');
 	untidy_links($map);
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -878,7 +919,7 @@ function deleteLink($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$target = wm_editor_sanitize_name(get_nfilter_request_var('param'));
 	$log    = 'delete link ' . $target;
@@ -886,7 +927,7 @@ function deleteLink($mapfile) {
 	if (isset($map->links[$target])) {
 		unset($map->links[$target]);
 
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -903,7 +944,7 @@ function addNode($mapfile, $grid_snap_value) {
 	$x = snap(intval(get_nfilter_request_var('x')), $grid_snap_value);
 	$y = snap(intval(get_nfilter_request_var('y')), $grid_snap_value);
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$newnodename = sprintf('node%05d', time() % 10000);
 
@@ -932,7 +973,7 @@ function addNode($mapfile, $grid_snap_value) {
 	$map->nodes[$node->name] = $node;
 	$log                     = "added a node called $newnodename at $x,$y to $mapfile";
 
-	$map->WriteConfig($mapfile);
+	wm_editor_write_config($map, $mapfile);
 }
 
 /**
@@ -947,7 +988,7 @@ function editorSettings($mapfile) {
 	$map->context = 'editor';
 
 	// have to do this, otherwise the editor will be unresponsive afterwards - not actually going to change anything!
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$use_overlay          = (isset_request_var('editorsettings_showvias') ? intval(get_nfilter_request_var('editorsettings_showvias')) : false);
 	$use_relative_overlay = (isset_request_var('editorsettings_showrelative') ? intval(get_nfilter_request_var('editorsettings_showrelative')) : false);
@@ -966,10 +1007,14 @@ function deleteNode($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$target = wm_editor_sanitize_name(get_nfilter_request_var('param'));
 
+	if (!isset($map->nodes[$target])) {
+		http_response_code(404);
+		return;
+	}
 	if (isset($map->nodes[$target])) {
 		$log = 'delete node ' . $target;
 
@@ -983,7 +1028,7 @@ function deleteNode($mapfile) {
 
 		unset($map->nodes[$target]);
 
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -996,7 +1041,7 @@ function cloneNode($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	$target = wm_editor_sanitize_name(get_nfilter_request_var('param'));
 
@@ -1027,7 +1072,7 @@ function cloneNode($mapfile) {
 
 		array_push($map->seen_zlayers[$node->zorder], $node);
 
-		$map->WriteConfig($mapfile);
+		wm_editor_write_config($map, $mapfile);
 	}
 }
 
@@ -1040,7 +1085,7 @@ function displayFontSamples($mapfile) {
 
 	$map->context = 'editor';
 
-	$map->ReadConfig($mapfile);
+	if (!wm_editor_read_config($map, $mapfile)) return;
 
 	ksort($map->fonts);
 	header('Content-type: image/png');
@@ -1138,3 +1183,26 @@ function getImageURL($mapname, $selected) {
 
 	return $imageurl;
 }
+
+/**
+ * Save a note through the authenticated editor request path.
+ *
+ * @param string $mapfile Validated configuration path.
+ * @param int $grid_snap_value Placement grid spacing.
+ *
+ * @return void
+ */
+function setNoteProperties($mapfile, $grid_snap_value) {
+	$map = new WeatherMap;
+	$map->context = 'editor';
+	if (!wm_editor_read_config($map, $mapfile)) return;
+	$values = [];
+	foreach (['name', 'text', 'font', 'colour', 'x', 'y', 'align'] as $field) {
+		$values[$field] = get_nfilter_request_var('note_' . $field);
+	}
+	if (!wm_editor_save_note($map, $values, $grid_snap_value)) {
+		http_response_code(400);
+		return;
+	}
+	wm_editor_write_config($map, $mapfile);
+}
diff --git a/lib/editor.comment-style.php b/lib/editor.comment-style.php
index 10fe830..702c963 100644
--- a/lib/editor.comment-style.php
+++ b/lib/editor.comment-style.php
@@ -117,7 +117,7 @@ function wm_style_font_options($map, $current) {
 		foreach ($bundled as $key => $choice) {
 			$value    = $matches[$key] ?? $choice['value'];
 			$selected = isset($matches[$key]) && $current == $matches[$key];
-			$out .= '<option value="' . html_escape((string)$value) . '"' . ($selected ? ' selected' : '') . '>' . html_escape($choice['label']) . '</option>';
+			$out .= '<option value="' . html_escape((string)$value) . '"' . ($selected ? ' selected' : '') . ($choice['value'] === 'bundled:Vera.ttf:9' ? ' data-wm-note-default="1"' : '') . '>' . html_escape($choice['label']) . '</option>';
 		}
 		$out .= '</optgroup>';
 	}
diff --git a/lib/editor.config-delete.php b/lib/editor.config-delete.php
index b438f7e..9d44560 100644
--- a/lib/editor.config-delete.php
+++ b/lib/editor.config-delete.php
@@ -90,45 +90,52 @@ function wm_config_delete($directory, $file) {
 		strpos($file, chr(92)) !== false || preg_match('/[\x00-\x1f\x7f]/', $file) || substr($file, -5) !== '.conf' || !$directory) {
 		return 'invalid';
 	}
-	$path     = $directory . '/' . $file;
-	$resolved = realpath($path);
-
-	if (is_link($path) || !is_file($path) || $resolved === false || dirname($resolved) !== $directory) {
-		return 'invalid';
-	}
-
-	$lock = wm_config_lock($path);
-	if ($lock === false) {
-		return 'failed';
-	}
+	require_once __DIR__ . '/WeatherMap.config.php';
+	$directory_lock = \WeathermapConfig\acquire($directory, false);
+	if (!$directory_lock) return 'failed';
 	try {
-		$usage = db_fetch_cell_prepared('SELECT COUNT(*) FROM weathermap_maps WHERE configfile IN (?, ?)', [$file, $path]);
-
-		if ($usage === false || $usage === null) {
-			return 'failed';
-		}
+		$path     = $directory . '/' . $file;
+		$resolved = realpath($path);
 
-		if ($usage) {
-			return 'used';
+		if (is_link($path) || !is_file($path) || $resolved === false || dirname($resolved) !== $directory) {
+			return 'invalid';
 		}
 
-		// Existing registrations may use ./, absolute paths or other aliases.
-		$maps = db_fetch_assoc_prepared('SELECT configfile FROM weathermap_maps', []);
-		if (!is_array($maps)) {
+		$lock = wm_config_lock($path);
+		if ($lock === false) {
 			return 'failed';
 		}
-		foreach ($maps as $map) {
-			$registered = $map['configfile'];
-			$registered_path = realpath(wm_config_registered_path($directory, $registered));
-			if ($registered_path === $resolved) {
+		try {
+			$usage = db_fetch_cell_prepared('SELECT COUNT(*) FROM weathermap_maps WHERE configfile IN (?, ?)', [$file, $path]);
+
+			if ($usage === false || $usage === null) {
+				return 'failed';
+			}
+
+			if ($usage) {
 				return 'used';
 			}
-		}
 
-		return @unlink($path) ? 'deleted' : 'failed';
+			// Existing registrations may use ./, absolute paths or other aliases.
+			$maps = db_fetch_assoc_prepared('SELECT configfile FROM weathermap_maps', []);
+			if (!is_array($maps)) {
+				return 'failed';
+			}
+			foreach ($maps as $map) {
+				$registered = $map['configfile'];
+				$registered_path = realpath(wm_config_registered_path($directory, $registered));
+				if ($registered_path === $resolved) {
+					return 'used';
+				}
+			}
+
+			return @unlink($path) ? 'deleted' : 'failed';
+		} finally {
+			flock($lock, LOCK_UN);
+			fclose($lock);
+		}
 	} finally {
-		flock($lock, LOCK_UN);
-		fclose($lock);
+		\WeathermapConfig\release($directory_lock);
 	}
 }
 /**
diff --git a/lib/editor.inc.php b/lib/editor.inc.php
index 50d97c5..57ff6e6 100644
--- a/lib/editor.inc.php
+++ b/lib/editor.inc.php
@@ -41,6 +41,7 @@
 */
 
 require_once __DIR__ . '/editor.comment-style.php';
+require_once __DIR__ . '/editor.notes.php';
 
 /** editor.inc.php
  *
@@ -1019,6 +1020,8 @@ function getEditorJs() {
 		'iconMatchCount' => __('Matching icons: %s', '%s', 'weathermap'),
 		'iconNoMatches' => __('No matching icons', 'weathermap'),
 
+		'staleError' => __('This map has changed since you opened it. Reload the editor before saving your changes.', 'weathermap'),
+		'saveError' => __('Unable to save changes. Please try again.', 'weathermap'),
 		'currentInterface'     => __('Current interface', 'weathermap'),
 		'advanced'             => __('Advanced settings', 'weathermap'),
 		'hideAdvanced'         => __('Hide advanced settings', 'weathermap'),
@@ -1026,6 +1029,12 @@ function getEditorJs() {
 		'changeInterface'      => __('Change interface', 'weathermap'),
 		'searchInterface'      => __('Search device or interface', 'weathermap'),
 		'noInterface'          => __('No interface selected', 'weathermap'),
+		'addNoteHelp' => __('Click on the map where you would like to add a note.', 'weathermap'),
+		'noteTitle' => __('Note', 'weathermap'),
+		'noteDeleteTitle' => __('Delete Note Confirmation', 'weathermap'),
+		'noteDeleteAction' => __('Delete Note', 'weathermap'),
+		'noteDelete' => __('Delete note "%s"?', '%s', 'weathermap'),
+		'noteError' => __('Unable to save changes. Please try again.', 'weathermap'),
 		'currentGraph'         => __('Current graph: %s', '%s', 'weathermap'),
 		'customConfig'         => __('Custom configuration — details under Advanced', 'weathermap'),
 		'chooseInterface'      => __('Choose an interface below', 'weathermap'),
diff --git a/lib/editor.notes.php b/lib/editor.notes.php
new file mode 100644
index 0000000..b6dfb0a
--- /dev/null
+++ b/lib/editor.notes.php
@@ -0,0 +1,159 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+
+/**
+ * Determine logical dimensions after background sizing and post-processing.
+ * @param WeatherMap $map Loaded editor snapshot.
+ * @return int[] Effective width and height without changing the saved configuration.
+ */
+function wm_note_effective_dimensions($map) {
+	$preview = clone $map;
+	$preview->image = null;
+	$preview->imap = new HTML_ImageMap('weathermap');
+	foreach ($preview->nodes as $name => $node) {
+		$preview->nodes[$name] = clone $node;
+		$preview->nodes[$name]->owner = $preview;
+		$preview->nodes[$name]->image = null;
+	}
+	foreach ($preview->links as $name => $link) {
+		$preview->links[$name] = clone $link;
+		$preview->links[$name]->owner = $preview;
+		foreach (['a', 'b'] as $end) if ($link->$end instanceof WeatherMapNode) $preview->links[$name]->$end = $preview->nodes[$link->$end->name];
+	}
+	foreach ($preview->seen_zlayers as $layer => $items) {
+		foreach ($items as $key => $item) {
+			if ($item instanceof WeatherMapNode) $preview->seen_zlayers[$layer][$key] = $preview->nodes[$item->name];
+			elseif ($item instanceof WeatherMapLink) $preview->seen_zlayers[$layer][$key] = $preview->links[$item->name];
+		}
+	}
+	foreach ($preview->plugins['post'] as $name => $plugin) $preview->plugins['post'][$name] = clone $plugin;
+	try {
+		if (function_exists('fixMapBackgroundAndImages')) fixMapBackgroundAndImages($preview);
+		$preview->DrawMap('null');
+		return [(int)$preview->width, (int)$preview->height];
+	} finally {
+		$preview->CleanUp();
+	}
+}
+
+/**
+ * Create or update a label-only note using existing map node directives.
+ *
+ * @param WeatherMap $map Map being edited.
+ * @param array<string, mixed> $values Submitted note fields.
+ * @param int $grid_snap_value Placement grid spacing.
+ *
+ * @return bool Whether the note was changed.
+ */
+function wm_editor_save_note($map, $values, $grid_snap_value = 0) {
+	$name = $values['name'] ?? '';
+	$text = $values['text'] ?? '';
+	$colour = $values['colour'] ?? '';
+	$alignment = $values['align'] ?? 'left';
+	if (!in_array($alignment, ['left', 'centre', 'right'], true)) {
+		return false;
+	}
+	if (!is_string($name) || !is_string($text) || trim($text) === '' || strlen($text) > 2000
+		|| preg_match('/[\x00-\x08\x0b\x0c\x0e-\x1f\x7f]/', $text)
+		|| !is_string($colour) || !preg_match('/^#[0-9a-f]{6}$/iD', $colour)) {
+		return false;
+	}
+	foreach (['x', 'y'] as $axis) {
+		if (!isset($values[$axis]) || !is_scalar($values[$axis]) || !preg_match('/^\d{1,6}$/D', (string)$values[$axis])) {
+			return false;
+		}
+	}
+	[$width, $height] = wm_note_effective_dimensions($map);
+	$x = (int)$values['x'];
+	$y = (int)$values['y'];
+	if ($x > $width || $y > $height) {
+		return false;
+	}
+	if ($name !== '' && (!isset($map->nodes[$name]) || $map->nodes[$name]->get_hint('editor_note', '0') !== '1')) {
+		return false;
+	}
+	$selection = $values['font'] ?? null;
+	$font = (is_string($selection) || is_int($selection)) && preg_match('/^\d+$/D', (string)$selection)
+		? wm_note_font_id($map, (string)$selection) : wm_comment_resolve_font($map, $selection);
+	if ($font === null) {
+		return false;
+	}
+	$font = wm_note_font_id($map, $font);
+	if ($name === '') {
+		do {
+			$name = 'note_' . bin2hex(random_bytes(6));
+		} while (isset($map->nodes[$name]));
+		$node = new WeatherMapNode;
+		$node->name = $name;
+		$node->template = 'DEFAULT';
+		$node->Reset($map);
+		$node->defined_in = $map->configfile;
+		$node->iconfile = '';
+		$node->targets = [];
+		$node->infourl = [IN => '', OUT => ''];
+		$node->overliburl = [IN => [], OUT => []];
+		$node->notestext = [IN => '', OUT => ''];
+		$node->labelbgcolour = [-1, -1, -1];
+		$node->labeloutlinecolour = [-1, -1, -1];
+		$node->labelfontshadowcolour = [-1, -1, -1];
+		$node->labeloffset = '';
+		$node->labeloffsetx = 0;
+		$node->labeloffsety = 0;
+		$node->labelangle = 0;
+		$node->relative_to = '';
+		$node->add_hint('editor_note', '1');
+		$map->nodes[$name] = $node;
+		$map->seen_zlayers[$node->zorder][] = $node;
+	}
+	$node = $map->nodes[$name];
+	$node->label = str_replace(["\r\n", "\r", "\n"], '\n', str_replace('\\', '\\\\', trim($text)));
+	$node->add_hint('editor_note_escaped', '1');
+	$node->labelfont = $font;
+	$node->add_hint('editor_note_align', $alignment);
+	$node->labelfontcolour = [hexdec(substr($colour, 1, 2)), hexdec(substr($colour, 3, 2)), hexdec(substr($colour, 5, 2))];
+	$node->x = min($width, snap($x, $grid_snap_value));
+	$node->y = min($height, snap($y, $grid_snap_value));
+	return true;
+}
+/**
+ * Expose note style data alongside the editor's existing node data.
+ *
+ * @param WeatherMap $map Map being edited.
+ *
+ * @return array<string, array<string, mixed>> Notes indexed by node name.
+ */
+function wm_editor_note_data($map) {
+	$notes = [];
+	foreach ($map->nodes as $name => $node) {
+		if ($node->get_hint('editor_note', '0') !== '1' || $name === 'DEFAULT') {
+			continue;
+		}
+		$fontId = wm_note_font_id($map, $node->labelfont);
+		$font = $map->fonts[$fontId];
+		$rgb = $node->labelfontcolour;
+		$notes[$name] = ['text' => $node->get_hint('editor_note_escaped', '0') === '1' ? wm_note_decode_text($node->label) : str_replace('\\n', "\n", $node->label), 'align' => $node->get_hint('editor_note_align', 'left'), 'font' => (string)$fontId, 'fontLabel' => wm_editor_font_label($fontId, $font),
+			'colour' => sprintf('#%02x%02x%02x', max(0, $rgb[0]), max(0, $rgb[1]), max(0, $rgb[2]))];
+	}
+	return $notes;
+}
diff --git a/lib/poller-common.php b/lib/poller-common.php
index f5f7510..2b17a3d 100644
--- a/lib/poller-common.php
+++ b/lib/poller-common.php
@@ -111,6 +111,47 @@ function weathermap_check_cron($time, $string) {
 	return ($matched);
 }
 
+/**
+ * Read a regular managed raster only after successful decoding.
+ * @param string $path Asset filename.
+ * @return string|false Validated image bytes, or false.
+ */
+function weathermap_read_raster($path) {
+	if (is_link($path) || !is_file($path) || !in_array(strtolower(pathinfo($path, PATHINFO_EXTENSION)), ['png', 'jpg', 'jpeg', 'gif'], true)) return false;
+	$contents = @file_get_contents($path);
+	if ($contents === false) return false;
+	$info = @getimagesizefromstring($contents);
+	if ($info === false || !in_array($info[2], [IMAGETYPE_PNG, IMAGETYPE_JPEG, IMAGETYPE_GIF], true)) return false;
+	set_error_handler(function () { return true; }, E_WARNING);
+	try { $image = imagecreatefromstring($contents); } finally { restore_error_handler(); }
+	if ($image === false) return false;
+	imagedestroy($image);
+	return $contents;
+}
+
+/**
+ * Stage a complete legacy asset copy while keeping every old map reference usable.
+ *
+ * @param string $old Source asset path.
+ * @param string $new New asset path.
+ * @return bool Whether a complete copy was reserved at the destination.
+ */
+function weathermap_stage_asset_copy($old, $new) {
+	global $config;
+	require_once __DIR__ . '/WeatherMap.config.php';
+	$root = realpath($config['base_path'] . '/plugins/weathermap');
+	$source = realpath($old);
+	$destination = realpath(dirname($new));
+	if ($root === false || $source === false || $destination === false) return false;
+	$root = str_replace('\\', '/', $root); $source = str_replace('\\', '/', $source); $destination = str_replace('\\', '/', $destination);
+	if (!str_starts_with($source, $root . '/')
+		|| !in_array($destination, [$root . '/images/objects', $root . '/images/backgrounds'], true)
+		|| !in_array(strtolower(pathinfo($source, PATHINFO_EXTENSION)), ['png', 'jpg', 'jpeg', 'gif'], true)) return false;
+	$contents = weathermap_read_raster($source);
+	if ($contents === false) return false;
+	return \WeathermapConfig\atomicWrite($new, $contents, false, null, true);
+}
+
 /**
  * @return void
  */
@@ -142,44 +183,54 @@ function weathermap_repair_maps() {
 			wm_debug('---------------------------------------------');
 			wm_debug("Processing Map File $configfile");
 
-			if (file_exists($configfile) && is_writable($configfile)) {
-				$contents    = file($configfile) ?: [];
+			if (!is_file($configfile) || !is_writable($configfile)) continue;
+			$contents = file($configfile);
+			if ($contents === false) continue;
+			$revision = hash('sha256', implode('', $contents));
+			require_once __DIR__ . '/WeatherMap.config.php';
+			$repairLock = \WeathermapConfig\acquire($confdir);
+			if (!$repairLock) { wm_warn('Unable to lock repaired configuration: ' . $configfile . ' [WMPOLL13]'); continue; }
+			try {
+				if (file_exists($configfile) && is_writable($configfile)) {
 
-				foreach ($contents as $line) {
-					if (strpos($line, 'BACKGROUND') !== false) {
-						$parts   = explode('BACKGROUND', $line);
-						$dirgood = false;
-						$bgfile  = trim($parts[1]);
+					foreach ($contents as $line) {
+						if (strpos($line, 'BACKGROUND') !== false) {
+							$parts   = explode('BACKGROUND', $line);
+							$dirgood = false;
+							$bgfile  = trim($parts[1]);
 
-						if (strpos($bgfile, 'images/backgrounds/') === false) {
-							wm_debug('Found background file reference in old location: ' . $bgfile);
+							if (strpos($bgfile, 'images/backgrounds/') === false) {
+								wm_debug('Found background file reference in old location: ' . $bgfile);
 
-							if (file_exists($mydir . 'images/backgrounds/' . basename($bgfile))) {
-								wm_debug('Background file found in new location! Updating path only.');
+								if (weathermap_read_raster($mydir . 'images/backgrounds/' . basename($bgfile)) !== false) {
+									wm_debug('Background file found in new location! Updating path only.');
 
-								$line = 'BACKGROUND images/backgrounds/' . basename($bgfile);
-
-								$changes++;
-							} else {
-								wm_debug('Background file not found in new location! Attempting to move.');
+									$line = 'BACKGROUND images/backgrounds/' . basename($bgfile);
 
-								if (!is_dir($mydir . 'images/backgrounds')) {
-									$dirgood = mkdir($mydir . 'images/backgrounds');
+									$changes++;
 								} else {
-									$dirgood = true;
-								}
+									wm_debug('Background file not found in new location! Attempting to move.');
+
+									if (!is_dir($mydir . 'images/backgrounds')) {
+										$dirgood = mkdir($mydir . 'images/backgrounds');
+									} else {
+										$dirgood = true;
+									}
 
-								if ($dirgood && file_exists($mydir . $bgfile)) {
-									wm_debug('Found background file on disk: ' . $mydir . $bgfile . ' relocating!');
+									if ($dirgood && file_exists($mydir . $bgfile)) {
+										wm_debug('Found background file on disk: ' . $mydir . $bgfile . ' relocating!');
 
-									$old = $mydir . $bgfile;
-									$new = $mydir . 'images/backgrounds/' . basename($bgfile);
+										$old = $mydir . $bgfile;
+										$new = $mydir . 'images/backgrounds/' . basename($bgfile);
 
-									if (is_writable($mydir . $bgfile)) {
-										if (is_writeable($old) && is_writeable(dirname($new)) && is_writeable($new)) {
-											if (rename($old, $new)) {
-												$line = 'BACKGROUND images/backgrounds/' . basename($bgfile);
-												$changes++;
+										if (is_readable($mydir . $bgfile)) {
+											if (is_readable($old) && is_writeable(dirname($new))) {
+												if (weathermap_stage_asset_copy($old, $new)) {
+													$line = 'BACKGROUND images/backgrounds/' . basename($bgfile);
+													$changes++;
+												} else {
+													wm_warn(sprintf('Unable to move BACKGROUND %s to %s, Permission error [WMPOLL09]', $old, $new));
+												}
 											} else {
 												wm_warn(sprintf('Unable to move BACKGROUND %s to %s, Permission error [WMPOLL09]', $old, $new));
 											}
@@ -187,65 +238,67 @@ function weathermap_repair_maps() {
 											wm_warn(sprintf('Unable to move BACKGROUND %s to %s, Permission error [WMPOLL09]', $old, $new));
 										}
 									} else {
-										wm_warn(sprintf('Unable to move BACKGROUND %s to %s, Permission error [WMPOLL09]', $old, $new));
+										wm_warn(sprintf('BACKGROUND file not found on disk: %s skipping! [WMPOLL10]', $mydir . $bgfile));
 									}
-								} else {
-									wm_warn(sprintf('BACKGROUND file not found on disk: %s skipping! [WMPOLL10]', $mydir . $bgfile));
 								}
+							} elseif (strpos($bgfile, 'images/backgrounds/') !== false) {
+								wm_debug('Found background file reference in correct location: ' . $bgfile);
 							}
-						} elseif (strpos($bgfile, 'images/backgrounds/') !== false) {
-							wm_debug('Found background file reference in correct location: ' . $bgfile);
-						}
-					} elseif (strpos($line, 'ICON') !== false) {
-						/**
-						 * We are looking at the ICON parameter.  It can take two forms.  The first form is
-						 * a path to a filename, or the pattern as follows
-						 *
-						 * ICON height width type
-						 *
-						 * Types include:
-						 *
-						 * - box - a square cornered box
-						 * - rbox - a round cornered box
-						 * - round - a circle or an ellipse
-						 * - inpie & outpie to produce a pie chart of either the in or out value relative to it's maximum
-						 * - nlink - to produce a circular 'yin-yang' style symbox with each half showing the in and out values
-						 *
-						 */
-						$parts   = explode('ICON', $line);
-						$dirgood = false;
-						$attribs = explode(' ', $parts[1]);
-
-						if (cacti_sizeof($attribs) == 1) {
-							$objfile = trim($parts[1]);
-
-							if (strpos($objfile, 'images/objects/') === false) {
-								wm_debug('Found icon file reference in old location: ' . $objfile);
-
-								if (file_exists($mydir . 'images/objects/' . basename($objfile))) {
-									wm_debug('Found file already in new location! Updating path only.');
-
-									$line = "\tICON images/objects/" . basename($objfile);
-
-									$changes++;
-								} else {
-									if (!is_dir($mydir . 'images/objects')) {
-										$dirgood = mkdir($mydir . 'images/objects');
+						} elseif (strpos($line, 'ICON') !== false) {
+							/**
+							 * We are looking at the ICON parameter.  It can take two forms.  The first form is
+							 * a path to a filename, or the pattern as follows
+							 *
+							 * ICON height width type
+							 *
+							 * Types include:
+							 *
+							 * - box - a square cornered box
+							 * - rbox - a round cornered box
+							 * - round - a circle or an ellipse
+							 * - inpie & outpie to produce a pie chart of either the in or out value relative to it's maximum
+							 * - nlink - to produce a circular 'yin-yang' style symbox with each half showing the in and out values
+							 *
+							 */
+							$parts   = explode('ICON', $line);
+							$dirgood = false;
+							$attribs = preg_split('/\s+/', trim($parts[1]));
+
+							if (cacti_sizeof($attribs) == 1 || (cacti_sizeof($attribs) == 3 && ctype_digit($attribs[0]) && ctype_digit($attribs[1]))) {
+								$objfile = end($attribs);
+								$dimensions = cacti_sizeof($attribs) == 3 ? $attribs[0] . ' ' . $attribs[1] . ' ' : '';
+								if (in_array(strtolower($objfile), ['box', 'rbox', 'round', 'inpie', 'outpie', 'gauge', 'nink', 'nlink', 'none'], true)) { $outcontents[] = rtrim($line); continue; }
+
+								if (strpos($objfile, 'images/objects/') === false) {
+									wm_debug('Found icon file reference in old location: ' . $objfile);
+
+									if (weathermap_read_raster($mydir . 'images/objects/' . basename($objfile)) !== false) {
+										wm_debug('Found file already in new location! Updating path only.');
+
+										$line = "\tICON " . $dimensions . "images/objects/" . basename($objfile);
+
+										$changes++;
 									} else {
-										$dirgood = true;
-									}
+										if (!is_dir($mydir . 'images/objects')) {
+											$dirgood = mkdir($mydir . 'images/objects');
+										} else {
+											$dirgood = true;
+										}
 
-									if ($dirgood && file_exists($mydir . $objfile)) {
-										wm_debug('Object file found on disk: ' . $mydir . $objfile . ' relocating!');
+										if ($dirgood && file_exists($mydir . $objfile)) {
+											wm_debug('Object file found on disk: ' . $mydir . $objfile . ' relocating!');
 
-										$old = $mydir . $objfile;
-										$new = $mydir . 'images/objects/' . basename($objfile);
+											$old = $mydir . $objfile;
+											$new = $mydir . 'images/objects/' . basename($objfile);
 
-										if (is_writable($mydir . $objfile)) {
-											if (is_writeable($old) && is_writeable(dirname($new)) && is_writeable($new)) {
-												if (rename($old, $new)) {
-													$line = "\tICON images/objects/" . basename($objfile);
-													$changes++;
+											if (is_readable($mydir . $objfile)) {
+												if (is_readable($old) && is_writeable(dirname($new))) {
+													if (weathermap_stage_asset_copy($old, $new)) {
+														$line = "\tICON " . $dimensions . "images/objects/" . basename($objfile);
+														$changes++;
+													} else {
+														wm_warn(sprintf('Unable to move ICONFILE %s to %s, Permission error [WMPOLL11]', $old, $new));
+													}
 												} else {
 													wm_warn(sprintf('Unable to move ICONFILE %s to %s, Permission error [WMPOLL11]', $old, $new));
 												}
@@ -253,28 +306,29 @@ function weathermap_repair_maps() {
 												wm_warn(sprintf('Unable to move ICONFILE %s to %s, Permission error [WMPOLL11]', $old, $new));
 											}
 										} else {
-											wm_warn(sprintf('Unable to move ICONFILE %s to %s, Permission error [WMPOLL11]', $old, $new));
+											wm_warn(sprintf('ICONFILE file not found on disk: %s skipping! [WMPOLL12]', $mydir . $objfile));
 										}
-									} else {
-										wm_warn(sprintf('ICONFILE file not found on disk: %s skipping! [WMPOLL12]', $mydir . $objfile));
 									}
+								} elseif (strpos($objfile, 'images/objects/') !== false) {
+									wm_debug('Found object file reference in correct location: ' . $objfile);
 								}
-							} elseif (strpos($objfile, 'images/objects/') !== false) {
-								wm_debug('Found object file reference in correct location: ' . $objfile);
 							}
 						}
-					}
 
-					$outcontents[] = rtrim($line);
+						$outcontents[] = rtrim($line);
+					}
 				}
-			}
 
-			if ($changes) {
-				wm_debug('Writing updated file to: ' . $configfile);
-				file_put_contents($configfile, implode("\n", $outcontents), LOCK_EX);
-			} else {
-				wm_debug('File has correct BACKGROUND and ICON paths: ' . $configfile);
-			}
+				if ($changes) {
+					wm_debug('Writing updated file to: ' . $configfile);
+					require_once __DIR__ . '/WeatherMap.config.php';
+					if (!\WeathermapConfig\atomicWrite($configfile, implode("\n", $outcontents), true, $revision, false, $repairLock)) {
+						wm_warn('Unable to save repaired configuration: ' . $configfile . ' [WMPOLL13]');
+					}
+				} else {
+					wm_debug('File has correct BACKGROUND and ICON paths: ' . $configfile);
+				}
+			} finally { \WeathermapConfig\release($repairLock); }
 		}
 	}
 }
diff --git a/locales/po/cacti.pot b/locales/po/cacti.pot
index 7c4a475..639626f 100644
--- a/locales/po/cacti.pot
+++ b/locales/po/cacti.pot
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: Cacti 1.7\n"
 "Report-Msgid-Bugs-To: developers@cacti.net\n"
-"POT-Creation-Date: 2026-10-12 12:29+1030\n"
+"POT-Creation-Date: 2026-10-13 23:15+1030\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: Cacti Developers <developers@cacti.net>\n"
 "Language-Team: Cacti Developers <developers@cacti.net>\n"
@@ -201,6 +201,14 @@ msgstr ""
 msgid "No matching icons"
 msgstr ""
 
+#: lib/editor.inc.php
+msgid "This map has changed since you opened it. Reload the editor before saving your changes."
+msgstr ""
+
+#: lib/editor.inc.php weathermap-cacti-plugin-editor.php
+msgid "Unable to save changes. Please try again."
+msgstr ""
+
 #: lib/editor.inc.php
 msgid "Current interface"
 msgstr ""
@@ -229,6 +237,27 @@ msgstr ""
 msgid "No interface selected"
 msgstr ""
 
+#: lib/editor.inc.php
+msgid "Click on the map where you would like to add a note."
+msgstr ""
+
+#: lib/editor.inc.php weathermap-cacti-plugin-editor.php
+msgid "Note"
+msgstr ""
+
+#: lib/editor.inc.php
+msgid "Delete Note Confirmation"
+msgstr ""
+
+#: lib/editor.inc.php weathermap-cacti-plugin-editor.php
+msgid "Delete Note"
+msgstr ""
+
+#: lib/editor.inc.php
+#, php-format
+msgid "Delete note \"%s\"?"
+msgstr ""
+
 #: lib/editor.inc.php
 #, php-format
 msgid "Current graph: %s"
@@ -964,6 +993,10 @@ msgstr ""
 msgid "Add<br>Link"
 msgstr ""
 
+#: weathermap-cacti-plugin-editor.php
+msgid "Add<br>Note"
+msgstr ""
+
 #: weathermap-cacti-plugin-editor.php
 msgid "Position<br>Legend"
 msgstr ""
@@ -1044,6 +1077,78 @@ msgstr ""
 msgid "See config"
 msgstr ""
 
+#: weathermap-cacti-plugin-editor.php
+msgid "Text"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Centre"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Left"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Right"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Text alignment"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Font"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Colour"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Note colour"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Black"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Blue"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Green"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Grey"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Orange"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Purple"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Red"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "White"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Custom colour"
+msgstr ""
+
+#: weathermap-cacti-plugin-editor.php
+msgid "Save"
+msgstr ""
+
 #: weathermap-cacti-plugin-editor.php
 msgid "Node Properties"
 msgstr ""
@@ -1084,10 +1189,6 @@ msgstr ""
 msgid "Edit"
 msgstr ""
 
-#: weathermap-cacti-plugin-editor.php
-msgid "Save"
-msgstr ""
-
 #: weathermap-cacti-plugin-editor.php
 msgid "You can modify the Weathermap Node from here.  The Position columns are the X,Y position on the Map.  The Internal Name is the unique ID given to the Node.  The Label is the external name of the Node that you provide to users.  The Icon Filename is the Graphic that you want to represent the Node Object.  The INFO URL is a link that you can provide when clicking on the active Map Node.  The Hover Graph URL's are Cacti or other Graphs URL's that can will appear when hovering over the Node.  The Graph Selector is a helper for selecting Cacti Graphs for the Graph URL's.   There are several other Node properties possible.  However, today we are only supporting those included above."
 msgstr ""
@@ -1780,23 +1881,25 @@ msgid "(No Title)"
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
-#, php-format
-msgid "The new Map with the name %s was created using config file %s"
+msgid "Could not lock map configurations."
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
 #, php-format
-msgid "The new Map %s was copied, but its title could not be updated in the config file %s"
+msgid "The new Map with the name %s was unable to locate the config file %s to copy"
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
-#, php-format
-msgid "The new Map with the name %s was unable to create the config file %s"
+msgid "Could not save the map configuration."
+msgstr ""
+
+#: weathermap-cacti-plugin-mgmt.php
+msgid "Could not register the new map."
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
 #, php-format
-msgid "The new Map with the name %s was unable to locate the config file %s to copy"
+msgid "The new Map with the name %s was created using config file %s"
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
@@ -2077,12 +2180,12 @@ msgid "The New Map File name %s already exists!"
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
-#, php-format
-msgid "New Map file %s created from %s"
+msgid "The Source Map File name is not readable or does not exist!"
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
-msgid "The Source Map File name is not readable or does not exist!"
+#, php-format
+msgid "New Map file %s created from %s"
 msgstr ""
 
 #: weathermap-cacti-plugin-mgmt.php
diff --git a/tests/Browser/EditorFilenameNavigationTest.cjs b/tests/Browser/EditorFilenameNavigationTest.cjs
index b62ea98..a64ef37 100644
--- a/tests/Browser/EditorFilenameNavigationTest.cjs
+++ b/tests/Browser/EditorFilenameNavigationTest.cjs
@@ -4,7 +4,7 @@ const fs = require('node:fs');
 const path = require('node:path');
 const vm = require('node:vm');
 const assert = require('node:assert/strict');
-const dom = new JSDOM('<input id="mapname" name="mapname"><input id="link_picker" class="selectmenu-ajax" data-action="graphs" value="7"><select id="link_template"><option value="1">One</option></select><div class="mapData"></div><img id="existingdata"><img id="xycapture"><input id="action">', {runScripts: 'outside-only'});
+const dom = new JSDOM('<input id="mapname" name="mapname"><input id="link_picker" class="selectmenu-ajax" data-action="graphs" value="7"><select id="link_template"><option value="1">One</option></select><div class="mapData"></div><img id="existingdata"><img id="xycapture"><input id="action">', {runScripts: 'outside-only', url:'https://example.test/editor.php?action=edit&config_revision=old&return_to=manage'});
 const w = dom.window, $ = jquery(w);
 w.$ = $;
 let pickerOptions;
@@ -29,13 +29,15 @@ for (const filename of ['ordinary.conf', 'A&B#C? +%é.conf']) {
   assert.equal(new URLSearchParams(options.data).get('mapname'), filename);
   options.success('');
  };
- $.get = (url, callback) => { check(url); callback(''); };
- $.getScript = (url, callback) => { check(url); callback(''); };
+ $.get = $.getScript = () => { throw Error('partial snapshot reload'); };
+ let reloadUrl;w.wmReloadEditor=()=>reloadUrl=w.wmEditorReloadUrl();
  $('#existingdata, #xycapture').attr('src', '?action=draw&mapname=' + encodeURIComponent(filename));
  w.form_submit();
- assert.deepEqual(requests, ['graphs', 'load_area_data', 'load_map_javascript']);
+ assert.deepEqual(requests, ['graphs']);
+ check(reloadUrl);
+ const reloaded=new URL(reloadUrl);assert.equal(reloaded.searchParams.get('action'),'nothing');assert.equal(reloaded.searchParams.has('config_revision'),false);assert.equal(reloaded.searchParams.get('return_to'),'manage');
  check($('#existingdata').attr('src'));
  check($('#xycapture').attr('src'));
 }
 w.close();
-console.log('PASS: picker, serialized save, map reload, JavaScript reload and image refresh retain ordinary and delimiter-containing filenames.');
+console.log('PASS: picker, serialized save, complete editor reload and image identity retain ordinary and delimiter-containing filenames.');
diff --git a/tests/Browser/EditorNotesTest.cjs b/tests/Browser/EditorNotesTest.cjs
new file mode 100644
index 0000000..9b03e72
--- /dev/null
+++ b/tests/Browser/EditorNotesTest.cjs
@@ -0,0 +1,51 @@
+// Exercise note placement, default/edit values and actual save/error handlers.
+const {JSDOM}=require('jsdom');
+const jquery=require('jquery');
+const fs=require('node:fs');
+const path=require('node:path');
+const assert=require('node:assert/strict');
+const fields=['action','param','node_name','note_name','note_text','note_x','note_y','note_colour','x','y','mapname'];
+const dom=new JSDOM('<body>'+fields.map(id=>id==='note_text'?`<textarea id="${id}" name="${id}"></textarea>`:`<input id="${id}" name="${id}">`).join('')+'<select id="note_font"><option value="bundled:Vera.ttf:9">Vera Sans — 9 pt</option></select><select id="note_align"><option>left</option><option>centre</option><option>right</option></select><div id="tb_help"></div><div id="note_advanced"></div><div id="wm-note-error"></div>'+['tb_addnote','note_clone','note_move','note_delete','note_advanced_toggle'].map(id=>`<button id="${id}"></button>`).join('')+'<button class="wm-note-colour" data-colour="#000000"></button></body>',{runScripts:'outside-only',pretendToBeVisual:true});
+const w=dom.window,$=jquery(w);w.$=w.jQuery=$;
+let mode,shown,moved,deleted,request;
+Object.assign(w,{Nodes:{note1:{label:'Core\\nMaintenance',x:50,y:60}},WMNotes:{note1:{align:'centre',font:'bundled:Vera.ttf:9',colour:'#cc0000'}},wmEditorText:{advanced:'Advanced',hideAdvanced:'Hide',addNoteHelp:'Place a note',noteError:'Save failed'},editor_url:'/editor',hide_all_dialogs:()=>$('#action').val(''),mapmode:m=>mode=m,show_dialog:id=>shown=id,hide_dialog:()=>{},move_node:()=>moved=$('#node_name').val(),delete_node:()=>deleted=$('#node_name').val()});
+$.fn.selectmenu=function(command){if(command==='refresh' && this.hasClass('select2-hidden-accessible'))throw Error('uninitialized selectmenu');return this;};
+$('#note_align').addClass('select2-hidden-accessible');
+const source=fs.readFileSync(path.join(__dirname,'../../js/editor.js'),'utf8');
+w.eval(source.slice(source.indexOf('// Notes are ordinary'),source.length));
+w.eval(source.slice(source.indexOf('function form_submit('),source.indexOf('function map_properties(')));
+w.eval(source.slice(source.indexOf("\t$('#tb_addnote')"),source.indexOf("\t$('#tb_poslegend')")));
+$('#tb_addnote').trigger('click');assert.equal($('#action').val(),'place_note');assert.equal(mode,'xy');
+$('#x').val('100');$('#y').val('120');w.form_submit();
+assert.equal(shown,'dlgNoteProperties');assert.equal($('#note_font').val(),'bundled:Vera.ttf:9');assert.equal($('#note_colour').val(),'#000000');assert.equal($('#note_align').val(),'left');assert.equal($('#note_x').val(),'100');
+$('#note_font').empty().append('<option value="10" data-wm-note-default="1">Translated Vera label (font 10)</option><option value="3">Builtin</option>');
+w.show_note('',10,20);assert.equal($('#note_font').val(),'10');
+w.show_note('note1');assert.equal($('#note_text').val(),'Core\nMaintenance');assert.equal($('#note_align').val(),'centre');
+w.WMNotes.note1.text='C:\\new site\nSecond line';w.show_note('note1');assert.equal($('#note_text').val(),w.WMNotes.note1.text);delete w.WMNotes.note1.text;
+$('#note_x,#note_y').attr('max',600);$('#note_clone').trigger('click');assert.equal($('#note_name').val(),'');assert.equal($('#note_x').val(),'70');
+w.show_note('note1');$('#note_move').trigger('click');assert.equal(moved,'note1');
+w.show_note('note1');$('#note_delete').trigger('click');assert.equal(deleted,'note1');assert.equal($('#param').val(),'note1');
+w.WMConfigRevision='a'.repeat(64);
+$.ajax=opts=>request=opts;w.show_note('note1');w.form_submit();
+assert.match(request.data,/config_revision=a{64}/);assert.equal(request.type,'POST');assert.match(request.data,/action=set_note_properties/);assert.match(request.data,/note_name=note1/);
+request.error();assert.equal($('#wm-note-error').text(),'Save failed');assert.notEqual($('#wm-note-error').css('display'),'none');assert.equal($('#note_name').val(),'note1');
+for(const action of ['move_node','delete_node']) {
+ w.show_note('note1');$('#node_name,#param').val('note1');$('#action').val(action);w.form_submit();request.error();
+ assert.equal(shown,'dlgNoteProperties');assert.equal($('#note_name').val(),'note1');assert.equal($('#wm-note-error').text(),'Save failed');
+}
+w.show_note('note1');w.form_submit();
+let refreshed=false;$.get=()=>{throw Error('partial editor refresh');};$.getScript=()=>{throw Error('token-only refresh');};w.wmReloadEditor=()=>refreshed=true;
+request.success('');assert.ok(refreshed);assert.equal($('#action').val(),'');
+// Exercise the real note-aware confirmation, including attached-link warning and target capture.
+w.eval(fs.readFileSync(path.join(process.env.CACTI_JS_DIR,'jquery-ui.js'),'utf8'));
+Object.assign(w,{Links:{attached:{a:'note1',b:'other'}},delNodePrompt:'Delete %s from this map?',delNodeConnected:'Connected links to remove: %s.',delNodeKeepDevice:'The Cacti device and graphs will remain.',delNodeTitle:'Delete Node',txtCancel:'Cancel',txtDelNode:'Delete Node',wmNodeDisplayName:()=> 'Core maintenance',form_submit:()=>{deleted=$('#param').val();}});
+Object.assign(w.wmEditorText,{noteDelete:'Delete note "%s"?',noteDeleteTitle:'Delete Note Confirmation',noteDeleteAction:'Delete Note'});
+w.eval(source.slice(source.indexOf('function delete_node()'),source.indexOf('function clone_node()')));
+$('#node_name').val('note1');w.delete_node();
+assert.equal($('.dlgConfirm').dialog('option','modal'),true);
+assert.equal($('.dlgConfirm').dialog('option','title'),'Delete Note Confirmation');
+assert.match($('.dlgConfirm').text(),/Delete note "Core maintenance"/);
+assert.match($('.dlgConfirm').text(),/Connected links to remove: 1/);
+assert.doesNotMatch($('.dlgConfirm').text(),/Cacti device/);
+$('#param').val('other_node');$('.dlgConfirm').dialog('option','buttons')[1].click.call($('.dlgConfirm')[0]);assert.equal(deleted,'note1');
+dom.window.close();console.log('PASS: note placement, defaults, edit, clone, move, guarded delete, save/error and refresh');
diff --git a/tests/Browser/EditorSaveFailureTest.cjs b/tests/Browser/EditorSaveFailureTest.cjs
new file mode 100644
index 0000000..0f5994d
--- /dev/null
+++ b/tests/Browser/EditorSaveFailureTest.cjs
@@ -0,0 +1,8 @@
+const {JSDOM}=require('jsdom'),jquery=require('jquery'),fs=require('node:fs'),path=require('node:path'),assert=require('node:assert/strict');
+const dom=new JSDOM('<input id="action" value="set_map_properties"><input id="mapname" value="map.conf">',{runScripts:'outside-only'}),w=dom.window,$=jquery(w);w.$=w.jQuery=$;w.editor_url='/editor';w.wmEditorText={staleError:'Reload the editor',saveError:'Unable to save changes'};
+let request,message,closed=0,refreshed=0;$.ajax=opts=>request=opts;w.alert=text=>message=text;w.hide_all_dialogs=()=>closed++;$.get=()=>refreshed++;
+const source=fs.readFileSync(path.join(__dirname,'../../js/editor.js'),'utf8');w.eval(source.slice(source.indexOf('function form_submit('),source.indexOf('function map_properties()')));
+w.form_submit();request.error();assert.equal(message,'Unable to save changes');assert.equal(closed,0);assert.equal(refreshed,0);assert.equal($('#action').val(),'set_map_properties');
+w.WMConfigRevision='b'.repeat(64);w.form_submit();assert.match(request.data,/config_revision=b{64}/);request.error({status:409});assert.equal(message,'Reload the editor');assert.equal(closed,0);assert.equal(refreshed,0);
+let reloads=0;w.hide_all_dialogs=()=>closed++;w.wmReloadEditor=()=>reloads++;$.get=()=>{throw Error('partial editor refresh');};request.success();assert.equal(reloads,1);
+w.close();console.log('PASS: save failure reports retry and preserves the form');
diff --git a/tests/Support/BackgroundSizingEngineRegression.php b/tests/Support/BackgroundSizingEngineRegression.php
index 98ad1a2..00b8457 100644
--- a/tests/Support/BackgroundSizingEngineRegression.php
+++ b/tests/Support/BackgroundSizingEngineRegression.php
@@ -100,5 +100,7 @@ public function run($map) {
 } finally {
 	foreach (glob($directory . '/*') as $file) {
 		unlink($file);
-	}rmdir($directory);
+	}
+	if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
+	rmdir($directory);
 }
diff --git a/tests/Support/ConfigWriteAtomicRegression.php b/tests/Support/ConfigWriteAtomicRegression.php
new file mode 100644
index 0000000..93a00cb
--- /dev/null
+++ b/tests/Support/ConfigWriteAtomicRegression.php
@@ -0,0 +1,629 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+
+namespace WeathermapConfig {
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param string $path
+	 * @param string $mode
+	 * @return resource|false
+	 */
+	function fopen($path, $mode) {
+		$fault = $GLOBALS['config_fault'] ?? '';
+		if (($fault === 'lock-open' && str_ends_with($path, '.lock')) || ($fault === 'lock-read' && $mode === 'c+b') || ($fault === 'temp-open' && $mode === 'wb')) return false;
+		return \fopen($path, $mode);
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param resource $stream
+	 * @param int $mode
+	 * @return bool
+	 */
+	function flock($stream, $mode) {
+		if (($GLOBALS['config_fault'] ?? '') === 'lock' && $mode === LOCK_EX) return false;
+		if (($mode & LOCK_EX) && isset($GLOBALS['config_before_lock'])) ($GLOBALS['config_before_lock'])();
+		return \flock($stream, $mode);
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param string $dir
+	 * @param string $prefix
+	 * @return string|false
+	 */
+	function tempnam($dir, $prefix) {
+		return ($GLOBALS['config_fault'] ?? '') === 'temp-name' ? false : \tempnam($dir, $prefix);
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param resource $stream
+	 * @param string $bytes
+	 * @return int|false
+	 */
+	function fwrite($stream, $bytes) {
+		$fault = $GLOBALS['config_fault'] ?? '';
+		if ($fault === 'write-false') return false;
+		if ($fault === 'write-zero') return 0;
+		return \fwrite($stream, $fault === 'short-write' ? substr($bytes, 0, 2) : $bytes);
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param resource $stream
+	 * @return bool
+	 */
+	function fflush($stream) {
+		return ($GLOBALS['config_fault'] ?? '') !== 'flush' && \fflush($stream);
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param resource $stream
+	 * @return bool
+	 */
+	function fclose($stream) {
+		$temp = strpos(stream_get_meta_data($stream)['uri'], '.wm-config-') !== false;
+		$closed = \fclose($stream);
+		return !(($GLOBALS['config_fault'] ?? '') === 'close' && $temp) && $closed;
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param string $path
+	 * @param int $group
+	 * @return bool
+	 */
+	function chgrp($path, $group) {
+		return ($GLOBALS['config_fault'] ?? '') !== 'group' && \chgrp($path, $group);
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param string $path
+	 * @param int $mode
+	 * @return bool
+	 */
+	function chmod($path, $mode) {
+		return ($GLOBALS['config_fault'] ?? '') !== 'mode' && \chmod($path, $mode);
+	}
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param string $source
+	 * @param string $target
+	 * @return bool
+	 */
+	function rename($source, $target) {
+		return ($GLOBALS['config_fault'] ?? '') !== 'rename' && \rename($source, $target);
+	}
+}
+namespace {
+	require dirname(__DIR__, 2) . '/lib/poller-common.php';
+	require dirname(__DIR__) . '/bootstrap-unit.php';
+	chdir(dirname(__DIR__, 2));
+	require dirname(__DIR__, 2) . '/setup.php';
+	require dirname(__DIR__, 2) . '/lib/WeatherMap.class.php';
+	require dirname(__DIR__, 2) . '/lib/WeatherMap.config.php';
+	require dirname(__DIR__, 2) . '/lib/editor.inc.php';
+	require dirname(__DIR__, 2) . '/lib/editor.actions.php';
+	/**
+	 * Simulate filesystem faults for an isolated atomic-write regression.
+	 *
+	 * @param bool $condition
+	 * @param string $message
+	 * @return void
+	 */
+	function atomic_assert($condition, $message) {
+		if (!$condition) throw new \RuntimeException($message);
+	}
+	$dir = sys_get_temp_dir() . '/wm-atomic-' . bin2hex(random_bytes(5));
+	mkdir($dir);
+	$file = $dir . '/map.conf';
+	$bitmap = imagecreatetruecolor(2, 2); ob_start(); imagepng($bitmap); $validAsset = ob_get_clean(); imagedestroy($bitmap);
+	$original = "WIDTH 600\nHEIGHT 300\nNODE note1\n LABEL Original\n POSITION 50 50\n SET editor_note 1\n";
+	file_put_contents($file, $original);
+	try {
+		foreach (array_filter(['lock-open', 'lock', 'temp-name', 'temp-open', 'write-false', 'write-zero', 'flush', 'close', 'group', 'mode', 'rename'], function($fault) { return PHP_OS_FAMILY !== 'Windows' || $fault !== 'group'; }) as $fault) {
+			$GLOBALS['config_fault'] = $fault;
+			atomic_assert(\WeathermapConfig\atomicWrite($file, 'Replacement') === false, 'failure propagated: ' . $fault);
+			atomic_assert(file_get_contents($file) === $original, 'original retained: ' . $fault);
+			atomic_assert(glob($dir . '/.wm-config-*') === [], 'temporary removed: ' . $fault);
+		}
+		$GLOBALS['config_fault'] = 'short-write';
+		atomic_assert(\WeathermapConfig\atomicWrite($file, 'Complete replacement'), 'short writes completed');
+		atomic_assert(file_get_contents($file) === 'Complete replacement', 'complete bytes retained');
+		$GLOBALS['config_fault'] = PHP_OS_FAMILY === 'Windows' ? '' : 'lock-read';
+		atomic_assert(\WeathermapConfig\atomicWrite($file, $original), 'readable lock supports another writer account');
+		$GLOBALS['config_fault'] = '';
+		atomic_assert(!\WeathermapConfig\atomicWrite('notewritefail://map/config', 'Replacement'), 'unsupported stream rejected');
+		atomic_assert(!\WeathermapConfig\atomicWrite($dir . '/missing/map.conf', 'Replacement'), 'missing directory rejected');
+		atomic_assert(!\WeathermapConfig\atomicWrite($dir, 'Replacement'), 'directory target rejected');
+		$link = $dir . '/link.conf';
+		if (@symlink($file, $link)) {
+			atomic_assert(\WeathermapConfig\atomicWrite($link, $original), 'configuration symlink target preserved');
+			atomic_assert(is_link($link), 'link itself retained'); unlink($link);
+		}
+		if (function_exists('pcntl_fork')) {
+			$lock = \WeathermapConfig\acquire($dir);
+			$child = pcntl_fork();
+			if ($child === 0) {
+				$probe = \fopen($dir . '/.weathermap-config.lock', 'rb');
+				$blocked = !\flock($probe, LOCK_EX | LOCK_NB); \fclose($probe);
+				exit($blocked ? 0 : 1);
+			}
+			pcntl_waitpid($child, $status); \WeathermapConfig\release($lock);
+			atomic_assert(pcntl_wexitstatus($status) === 0, 'shared lock excludes concurrent configuration writers');
+		}
+		// Deletion refuses a busy stable directory mutex rather than blocking the UI.
+		if (function_exists('pcntl_fork')) {
+			require_once dirname(__DIR__, 2) . '/lib/editor.config-delete.php';
+			$GLOBALS['__test_db_fetch_cell_prepared'] = fn () => 0;
+			$GLOBALS['__test_db_fetch_assoc_prepared'] = fn () => [];
+			$lock = \WeathermapConfig\acquire($dir);
+			$ready = $dir . '/ready'; $done = $dir . '/done';
+			$child = pcntl_fork();
+			if ($child === 0) {
+				\fclose($lock);
+				file_put_contents($ready, 'ready');
+				$result = wm_config_delete($dir, 'map.conf');
+				file_put_contents($done, $result);
+				exit($result === 'failed' ? 0 : 1);
+			}
+			for ($wait = 0; $wait < 100 && !is_file($done); $wait++) usleep(10000);
+			$blocked = is_file($done) && file_get_contents($done) === 'failed' && is_file($file);
+			\WeathermapConfig\release($lock);
+			pcntl_waitpid($child, $status);
+			atomic_assert($blocked && pcntl_wexitstatus($status) === 0, 'config deletion cannot unlink during a directory-locked write');
+			atomic_assert(wm_config_delete($dir, 'map.conf') === 'deleted', 'deletion succeeds after the writer releases its lock');
+			unlink($ready); unlink($done);
+			unset($GLOBALS['__test_db_fetch_cell_prepared'], $GLOBALS['__test_db_fetch_assoc_prepared']);
+			file_put_contents($file, $original);
+		}
+		atomic_assert(!\WeathermapConfig\acquire($dir . '/missing'), 'missing lock directory rejected');
+		atomic_assert(!\WeathermapConfig\atomicWrite($dir . '/deleted.conf', 'Replacement', true), 'deleted existing maps are not recreated');
+		atomic_assert(is_file($dir . '/.weathermap-config.lock'), 'arbitrary output uses its destination directory lock');
+		atomic_assert(!\WeathermapConfig\atomicWrite($file, 'Overwrite', false, null, true), 'create-only destination refuses existing files');
+		$first = new \WeatherMap; $second = new \WeatherMap;
+		$first->ReadConfig($file); $second->ReadConfig($file);
+		$first->title = 'First edit'; $second->title = 'Stale edit';
+		atomic_assert($first->WriteConfig($file), 'first revision saves');
+		$current = file_get_contents($file);
+		atomic_assert(!$second->WriteConfig($file) && file_get_contents($file) === $current, 'stale reader cannot overwrite the first edit');
+		$first->title = 'Next edit';
+		atomic_assert($first->WriteConfig($file), 'successful save updates its revision for subsequent writes');
+		$GLOBALS['__test_nfilter_request'] = ['config_revision' => hash('sha256', $original), 'node_name' => 'note1', 'x' => 90, 'y' => 90];
+		http_response_code(200); moveNode($file, 0);
+		atomic_assert(http_response_code() === 409 && file_get_contents($file) !== $original, 'stale loaded page cannot overwrite another user save');
+		$GLOBALS['__test_nfilter_request'] = ['config_revision' => hash_file('sha256', $file)];
+		$matching = new \WeatherMap;
+		atomic_assert(wm_editor_read_config($matching, $file), 'matching loaded page revision accepted');
+		$GLOBALS['__test_nfilter_request'] = [];
+		$raw = new \WeatherMap; wm_editor_read_config($raw, $file);
+		$raw->ReadConfig("TITLE Fragment edit\n");
+		file_put_contents($file, $original);
+		http_response_code(200);
+		atomic_assert(!wm_editor_write_config($raw, $file) && http_response_code() === 409 && file_get_contents($file) === $original, 'raw fragment edits retain the original request revision');
+		if (function_exists('pcntl_fork')) {
+			$createFile = $dir . '/create.conf';
+			$lock = \WeathermapConfig\acquire($dir); $children = [];
+			for ($index = 0; $index < 2; $index++) {
+				$child = pcntl_fork();
+				if ($child === 0) {
+					\fclose($lock);
+					$GLOBALS['config_before_lock'] = function() use ($dir, $index) { file_put_contents($dir . '/create-ready-' . $index, 'ready'); };
+					$saved = \WeathermapConfig\atomicWrite($createFile, 'Creator ' . $index, false, null, true);
+					file_put_contents($dir . '/create-result-' . $index, $saved ? '1' : '0');
+					exit(0);
+				}
+				$children[] = $child;
+			}
+			for ($wait = 0; $wait < 100 && cacti_count(glob($dir . '/create-ready-*')) < 2; $wait++) usleep(10000);
+			\WeathermapConfig\release($lock);
+			foreach ($children as $child) pcntl_waitpid($child, $status);
+			atomic_assert((int)file_get_contents($dir . '/create-result-0') + (int)file_get_contents($dir . '/create-result-1') === 1, 'exactly one concurrent creator commits');
+			atomic_assert(in_array(file_get_contents($createFile), ['Creator 0', 'Creator 1'], true), 'winning creator content remains intact');
+		}
+		$held = \WeathermapConfig\acquire($dir);
+		atomic_assert(\WeathermapConfig\atomicWrite($dir . '/held.conf', 'Held write', false, null, true, $held), 'caller-owned mutex supports atomic creation');
+		if (function_exists('pcntl_fork')) {
+			$child = pcntl_fork();
+			if ($child === 0) { $probe = \fopen($dir . '/.weathermap-config.lock', 'rb'); $busy = !\flock($probe, LOCK_EX | LOCK_NB); exit($busy ? 0 : 1); }
+			pcntl_waitpid($child, $status);
+			atomic_assert(pcntl_wexitstatus($status) === 0, 'atomicWrite leaves caller mutex held');
+		}
+		\WeathermapConfig\release($held);
+
+		$external = sys_get_temp_dir() . '/wm-external-' . bin2hex(random_bytes(5));
+		mkdir($external); $externalFile = $external . '/map.conf'; file_put_contents($externalFile, $original);
+		$alias = $dir . '/external.conf';
+		if (@symlink($externalFile, $alias)) {
+			$logicalLock = \WeathermapConfig\acquire($dir);
+			atomic_assert(\WeathermapConfig\atomicWrite($alias, $original, true, hash('sha256', $original), false, $logicalLock), 'external symlink accepts caller-held logical configuration mutex');
+			atomic_assert(is_file($external . '/.weathermap-config.lock'), 'symlink writes retain logical mutex and also acquire the physical target mutex');
+			\WeathermapConfig\release($logicalLock); unlink($alias);
+		}
+		unlink($externalFile); unlink($external . '/.weathermap-config.lock'); rmdir($external);
+
+		$includeFile = $dir . '/included.conf'; $includeRoot = $dir . '/include-root.conf';
+		file_put_contents($includeFile, "TITLE Included old\n");
+		$includeConfig = "WIDTH 600\nHEIGHT 300\nINCLUDE " . $includeFile . "\n";
+		file_put_contents($includeRoot, $includeConfig);
+		$dependent = new \WeatherMap; $dependent->ReadConfig($includeRoot);
+		$token = \WeathermapConfig\snapshotRevision($dependent->config_revision, $dependent->config_dependencies);
+		file_put_contents($includeFile, "TITLE Included winner\n"); $dependent->title = 'Stale edit';
+		atomic_assert(!$dependent->WriteConfig($includeRoot) && file_get_contents($includeRoot) === $includeConfig, 'included file changes reject stale root persistence');
+		$GLOBALS['__test_nfilter_request'] = ['config_revision' => $token]; http_response_code(200);
+		atomic_assert(!wm_editor_read_config(new \WeatherMap, $includeRoot) && http_response_code() === 409, 'included-file changes invalidate loaded editor page token');
+		$GLOBALS['__test_nfilter_request'] = []; $fresh = new \WeatherMap; $fresh->ReadConfig($includeRoot);
+		atomic_assert($fresh->WriteConfig($includeRoot), 'unchanged included dependency can be saved');
+		atomic_assert(!\WeathermapConfig\dependenciesMatch([$includeFile => null]), 'unread included dependency rejected');
+		$outside = $dir . '/dependency-directory'; mkdir($outside); $outsideFile = $outside . '/outside.conf'; file_put_contents($outsideFile, "TITLE Outside\n");
+		file_put_contents($includeRoot, "WIDTH 600\nHEIGHT 300\nINCLUDE " . $outsideFile . "\n");
+		$externalMap = new \WeatherMap; $externalMap->ReadConfig($includeRoot); $busy = \WeathermapConfig\acquire($outside);
+		atomic_assert(!$externalMap->WriteConfig($includeRoot), 'busy dependency directory rejects save without deadlock');
+		\WeathermapConfig\release($busy);
+		atomic_assert($externalMap->WriteConfig($includeRoot), 'external dependency save succeeds after mutex release');
+		unlink($outside . '/.weathermap-config.lock'); chmod($outside, 0555);
+		atomic_assert($externalMap->WriteConfig($includeRoot), 'read-only included dependency needs no new lock file');
+		chmod($outside, 0755); unlink($outsideFile); rmdir($outside);
+
+		$targetDir = $dir . '/alias-target'; mkdir($targetDir); $targetFile = $targetDir . '/map.conf'; file_put_contents($targetFile, $original);
+		$alias = $dir . '/alias.conf'; symlink($targetFile, $alias); $targetLock = \WeathermapConfig\acquire($targetDir);
+		atomic_assert(!\WeathermapConfig\atomicWrite($alias, 'Alias change', true, hash('sha256', $original)) && file_get_contents($targetFile) === $original, 'alias cannot bypass a held physical target mutex');
+		\WeathermapConfig\release($targetLock);
+		atomic_assert(\WeathermapConfig\atomicWrite($alias, $original, true, hash('sha256', $original)), 'alias save succeeds after shared target mutex release');
+
+		$lockCalls = 0;
+		$GLOBALS['config_before_lock'] = function () use (&$lockCalls, $targetFile) {
+			if (++$lockCalls === 2) file_put_contents($targetFile, 'Direct writer winner');
+		};
+		try {
+			atomic_assert(!\WeathermapConfig\atomicWrite($alias, 'Stale alias edit', true, hash('sha256', $original)) && file_get_contents($targetFile) === 'Direct writer winner', 'alias revision is checked after physical target lock acquisition');
+		} finally { unset($GLOBALS['config_before_lock']); }
+		file_put_contents($targetFile, "TITLE Physical include\n");
+		file_put_contents($includeRoot, "WIDTH 600\nHEIGHT 300\nINCLUDE " . $alias . "\n");
+		$aliasMap = new \WeatherMap; $aliasMap->ReadConfig($includeRoot);
+		atomic_assert(array_key_exists(realpath($targetFile), $aliasMap->config_dependencies), 'symlink include snapshot records physical filename');
+		$targetLock = \WeathermapConfig\acquire($targetDir);
+		atomic_assert(!$aliasMap->WriteConfig($includeRoot), 'symlink include cannot bypass physical dependency mutex');
+		\WeathermapConfig\release($targetLock);
+		atomic_assert($aliasMap->WriteConfig($includeRoot), 'symlink include save succeeds after dependency mutex release');
+		unlink($alias); unlink($targetFile); unlink($targetDir . '/.weathermap-config.lock'); rmdir($targetDir);
+
+		$numericLocale = setlocale(LC_NUMERIC, 0); setlocale(LC_NUMERIC, 'fr_FR.UTF-8', 'fr_FR.utf8', 'fr_FR');
+		try {
+			$largeScale = new \WeatherMap; $largeScale->ReadConfig("SCALE large 1500 2500 0 255 0\n");
+			atomic_assert($largeScale->WriteConfig($dir . '/large-scale.conf'), 'large scale saves under alternate locale');
+			$largeText = file_get_contents($dir . '/large-scale.conf'); atomic_assert(str_contains($largeText, '1.5K') && str_contains($largeText, '2.5K'), 'unit-suffixed ranges retain parser-compatible decimal points');
+		} finally { setlocale(LC_NUMERIC, $numericLocale); }
+		$wrong = \fopen($file, 'rb');
+		atomic_assert(!\WeathermapConfig\atomicWrite($dir . '/wrong-lock.conf', 'Wrong', false, null, true, $wrong), 'different lock file rejected'); \fclose($wrong);
+		// Revision metadata must describe the same map snapshot as the controls.
+		file_put_contents($file, $original); $snapshot = new \WeatherMap; $snapshot->ReadConfig($file);
+		$loadedRevision = $snapshot->config_revision;
+		$updatedSnapshot = str_replace('Original', 'NewSnapshot', $original); file_put_contents($file, $updatedSnapshot);
+		$GLOBALS['__test_nfilter_request'] = [];
+		ob_start(); getMapJavaScript($file, $snapshot); $javascript = ob_get_clean();
+		atomic_assert(str_contains($javascript, 'Original') && !str_contains($javascript, 'NewSnapshot') && str_contains($javascript, $loadedRevision), 'rendered values and revision come from one loaded snapshot');
+		$GLOBALS['__test_nfilter_request'] = ['config_revision' => $loadedRevision];
+		http_response_code(200); atomic_assert(!wm_editor_read_config(new \WeatherMap, $file) && http_response_code() === 409, 'concurrent save cannot be hidden by a refreshed token');
+		// Simulate deletion between the existence check and the engine file read.
+		class AtomicDeletedDuringReadMap extends \WeatherMap {
+			/** Simulate an engine load that loses its file before opening it. */
+			function ReadConfig($input, $is_include = false) { unlink($input); $this->config_revision = null; return true; }
+		}
+		foreach ([[], ['config_revision' => $loadedRevision]] as $request) {
+			file_put_contents($file, $original); $GLOBALS['__test_nfilter_request'] = $request;
+			http_response_code(200); atomic_assert(!wm_editor_read_config(new AtomicDeletedDuringReadMap, $file) && http_response_code() === 404, 'deletion race cannot proceed with a null revision');
+		}
+
+		$plugin = dirname(__DIR__, 2);
+		// Exercise both copy entry points with an engine that loses the source during loading.
+		$actions = file_get_contents($plugin . '/lib/editor.actions.php');
+		$copyStart = strpos($actions, 'function newMapCopy('); $copyEnd = strpos($actions, "\n/**", $copyStart);
+		eval(str_replace(['function newMapCopy(', 'new WeatherMap'], ['function atomicLostSourceCopy(', 'new AtomicDeletedDuringReadMap'], substr($actions, $copyStart, $copyEnd - $copyStart)));
+		$GLOBALS['mapdir'] = $dir; $GLOBALS['__test_request']['sourcemap'] = basename($file); $GLOBALS['__test_nfilter_request'] = ['sourcemap' => basename($file)];
+		file_put_contents($file, $original); http_response_code(200); atomicLostSourceCopy($dir . '/lost-copy.conf');
+		atomic_assert(http_response_code() === 404 && !is_file($dir . '/lost-copy.conf'), 'editor copy rejects source lost during load');
+		$managementCopy = file_get_contents($plugin . '/weathermap-cacti-plugin-mgmt.php');
+		eval(str_replace(['__DIR__', 'function newMap(', 'new WeatherMap'], [var_export($plugin, true), 'function atomicLostManagementCopy(', 'new AtomicDeletedDuringReadMap'], substr($managementCopy, strpos($managementCopy, 'function newMap('))));
+		$GLOBALS['weathermap_confdir'] = $dir; file_put_contents($file, $original);
+		atomicLostManagementCopy('lost-management-copy.conf', basename($file));
+		atomic_assert(!is_file($dir . '/lost-management-copy.conf'), 'management copy rejects source lost during load');
+		unset($GLOBALS['__test_request']['sourcemap']);
+		$GLOBALS['__test_nfilter_request'] = []; file_put_contents($file, $original);
+		$crlfFile = $dir . '/crlf.conf';
+		$crlf = "WIDTH 600\r\nHEIGHT 300\r\n"; file_put_contents($crlfFile, $crlf);
+		$crlfMap = new \WeatherMap; $crlfMap->ReadConfig($crlfFile);
+		atomic_assert($crlfMap->config_revision === hash('sha256', $crlf) && $crlfMap->WriteConfig($crlfFile), 'revision hashes preserve raw CRLF bytes');
+		$templateFile = $dir . '/templates.conf';
+		file_put_contents($templateFile, "NODE templateNode\n LABEL Template\nNODE A\n POSITION 10 10\nNODE B\n POSITION 50 50\nLINK templateLink\n WIDTH 8\nLINK trafficLink\n NODES A B\n");
+		$templateMap = new \WeatherMap; $templateMap->ReadConfig($templateFile);
+		atomic_assert($templateMap->WriteConfig($templateFile), 'atomic save supports templates and traffic links');
+		$reloaded = new \WeatherMap; $reloaded->ReadConfig($templateFile);
+		atomic_assert(isset($reloaded->nodes['templateNode'], $reloaded->links['templateLink'], $reloaded->links['trafficLink']), 'template and real objects survive atomic roundtrip');
+		$plugin = dirname(__DIR__, 2);
+		$repairName = 'atomic-repair-' . bin2hex(random_bytes(4)) . '.conf';
+		$repairFile = $plugin . '/configs/' . $repairName;
+		$repairImage = $plugin . '/images/backgrounds/' . $repairName . '.png';
+		$legacy = 'BACKGROUND ' . basename($repairImage) . "\n";
+		file_put_contents($repairFile, $legacy); file_put_contents($repairImage, $validAsset);
+		$oldConfig = $GLOBALS['config'];
+		$GLOBALS['config']['base_path'] = dirname($plugin, 2);
+		$GLOBALS['__test_db_fetch_assoc'] = fn ($sql) => [['configfile' => $repairName]];
+		try {
+			$GLOBALS['config_fault'] = 'rename';
+			$oldSuppress = $GLOBALS['weathermap_error_suppress'] ?? [];
+			$GLOBALS['weathermap_error_suppress'] = ['WMPOLL13'];
+			try { weathermap_repair_maps(); } finally { $GLOBALS['weathermap_error_suppress'] = $oldSuppress; }
+			atomic_assert(file_get_contents($repairFile) === $legacy, 'failed repair preserves original config');
+			$GLOBALS['config_fault'] = '';
+			weathermap_repair_maps();
+			atomic_assert(file_get_contents($repairFile) === 'BACKGROUND images/backgrounds/' . basename($repairImage), 'repair uses complete atomic replacement');
+			foreach (['corrupt', 'directory', 'symlink'] as $invalidTarget) {
+				unlink($repairImage); file_put_contents($repairFile, $legacy);
+				if ($invalidTarget === 'directory') mkdir($repairImage);
+				elseif ($invalidTarget === 'symlink') symlink($repairFile, $repairImage);
+				else file_put_contents($repairImage, 'corrupt image');
+				$GLOBALS['weathermap_error_suppress'] = ['WMPOLL10'];
+				try { weathermap_repair_maps(); } finally { $GLOBALS['weathermap_error_suppress'] = $oldSuppress; }
+				atomic_assert(file_get_contents($repairFile) === $legacy, 'repair retains legacy background for invalid existing target: ' . $invalidTarget);
+				if (is_dir($repairImage)) rmdir($repairImage); else unlink($repairImage);
+				file_put_contents($repairImage, $validAsset);
+			}
+			file_put_contents($repairFile, $legacy);
+			$newerRepair = 'TITLE Concurrent editor save' . "\n" . $legacy;
+			$GLOBALS['config_before_lock'] = function() use ($repairFile, $newerRepair) {
+				unset($GLOBALS['config_before_lock']);
+				file_put_contents($repairFile, $newerRepair);
+			};
+			$GLOBALS['weathermap_error_suppress'] = ['WMPOLL13'];
+			try { weathermap_repair_maps(); } finally { $GLOBALS['weathermap_error_suppress'] = $oldSuppress; }
+			atomic_assert(file_get_contents($repairFile) === $newerRepair, 'repair CAS preserves a concurrent editor save');
+		} finally {
+			$GLOBALS['config'] = $oldConfig;
+			unset($GLOBALS['__test_db_fetch_assoc']);
+			unlink($repairFile); unlink($repairImage);
+		}
+		$stageSource = $plugin . '/legacy-stage-' . bin2hex(random_bytes(4)) . '.png';
+		$stageTarget = $plugin . '/images/backgrounds/' . basename($stageSource);
+		file_put_contents($stageSource, $validAsset);
+
+		$outsideAsset = $dir . '/outside.png'; file_put_contents($outsideAsset, $validAsset);
+		atomic_assert(!weathermap_stage_asset_copy($outsideAsset, $stageTarget) && !is_file($stageTarget), 'repair rejects a valid image outside the legacy root');
+		$badAsset = $plugin . '/invalid-stage-' . bin2hex(random_bytes(4)) . '.png'; file_put_contents($badAsset, 'not an image');
+		atomic_assert(!weathermap_stage_asset_copy($badAsset, $stageTarget) && !is_file($stageTarget), 'repair rejects non-image bytes within the legacy root');
+		unlink($badAsset); unlink($outsideAsset);
+		$stageConfig = $plugin . '/configs/' . basename($stageSource) . '.conf';
+		$stageLegacy = 'BACKGROUND ' . basename($stageSource) . "\n";
+		file_put_contents($stageConfig, $stageLegacy);
+		$GLOBALS['__test_db_fetch_assoc'] = fn () => [['configfile' => basename($stageConfig)]];
+		$oldConfig = $GLOBALS['config']; $GLOBALS['config']['base_path'] = dirname($plugin, 2);
+		$oldSuppress = $GLOBALS['weathermap_error_suppress'] ?? [];
+		try {
+			// A staged copy succeeds, but the config CAS must fail after a concurrent save.
+			$staged = weathermap_stage_asset_copy($stageSource, $stageTarget);
+			atomic_assert($staged && is_file($stageSource) && file_get_contents($stageTarget) === $validAsset, 'staging keeps original and complete destination');
+			$stageNewer = "TITLE Concurrent repair edit\n" . $stageLegacy;
+			$GLOBALS['config_before_lock'] = function() use ($stageConfig, $stageNewer) { unset($GLOBALS['config_before_lock']); file_put_contents($stageConfig, $stageNewer); };
+			$GLOBALS['weathermap_error_suppress'] = ['WMPOLL13']; weathermap_repair_maps();
+			atomic_assert(file_get_contents($stageConfig) === $stageNewer && is_file($stageSource), 'rejected repair leaves original asset usable');
+			$GLOBALS['config_fault'] = 'rename'; weathermap_repair_maps();
+			atomic_assert(file_get_contents($stageConfig) === $stageNewer && is_file($stageSource), 'I/O failure leaves original asset usable');
+			$GLOBALS['config_fault'] = ''; unlink($stageTarget); file_put_contents($stageConfig, $stageLegacy);
+			weathermap_repair_maps();
+			atomic_assert(str_contains(file_get_contents($stageConfig), 'images/backgrounds/') && is_file($stageSource) && is_file($stageTarget), 'successful relocation copies rather than removes legacy asset');
+		} finally {
+			$GLOBALS['config'] = $oldConfig; $GLOBALS['weathermap_error_suppress'] = $oldSuppress; $GLOBALS['config_fault'] = '';
+			unset($GLOBALS['__test_db_fetch_assoc'], $GLOBALS['config_before_lock']);
+			foreach ([$stageSource, $stageTarget, $stageConfig] as $path) if (is_file($path)) unlink($path);
+		}
+		// Exercise legacy background and icon relocation in a separate filesystem tree.
+		$repairRoot = $dir . '/repair-fixture';
+		$repairPlugin = $repairRoot . '/cacti/plugins/weathermap';
+		mkdir($repairPlugin . '/configs', 0777, true); mkdir($repairPlugin . '/images');
+		symlink($plugin . '/lib', $repairPlugin . '/lib');
+		file_put_contents($repairPlugin . '/legacy-background.png', $validAsset);
+		file_put_contents($repairPlugin . '/legacy-icon.png', $validAsset);
+		$legacyFixture = "BACKGROUND legacy-background.png\nNODE Legacy\n ICON legacy-icon.png\n";
+		$fixtureConfig = $repairPlugin . '/configs/legacy.conf';
+		$oldConfig = $GLOBALS['config']; $oldSuppress = $GLOBALS['weathermap_error_suppress'] ?? [];
+		$GLOBALS['config']['base_path'] = $repairRoot . '/cacti';
+		$GLOBALS['__test_db_fetch_assoc'] = fn () => [['configfile' => 'legacy.conf']];
+		$GLOBALS['weathermap_error_suppress'] = ['WMPOLL09', 'WMPOLL10', 'WMPOLL11', 'WMPOLL12', 'WMPOLL13'];
+		try {
+			file_put_contents($fixtureConfig, $legacyFixture); weathermap_repair_maps();
+			$repairedFixture = file_get_contents($fixtureConfig);
+			atomic_assert(str_contains($repairedFixture, 'BACKGROUND images/backgrounds/legacy-background.png') && str_contains($repairedFixture, 'ICON images/objects/legacy-icon.png'), 'repair creates libraries and copies both legacy asset kinds');
+			atomic_assert(is_file($repairPlugin . '/legacy-background.png') && is_file($repairPlugin . '/legacy-icon.png'), 'successful repair preserves both original assets');
+			file_put_contents($fixtureConfig, $legacyFixture); weathermap_repair_maps();
+			atomic_assert(file_get_contents($fixtureConfig) === $repairedFixture, 'existing complete copies support path-only repair');
+			weathermap_repair_maps(); atomic_assert(file_get_contents($fixtureConfig) === $repairedFixture, 'correct paths require no rewrite');
+			$sizedLegacy = "NODE Sized\n ICON 100 80 legacy-icon.png\nNODE Shape\n ICON 30 40 box\n";
+			file_put_contents($fixtureConfig, $sizedLegacy); weathermap_repair_maps();
+			atomic_assert(str_contains(file_get_contents($fixtureConfig), 'ICON 100 80 images/objects/legacy-icon.png') && str_contains(file_get_contents($fixtureConfig), 'ICON 30 40 box'), 'sized legacy icon repair preserves dimensions and built-in shapes');
+			unlink($repairPlugin . '/images/objects/legacy-icon.png'); file_put_contents($fixtureConfig, $sizedLegacy); weathermap_repair_maps();
+			atomic_assert(str_contains(file_get_contents($fixtureConfig), 'ICON 100 80 images/objects/legacy-icon.png') && is_file($repairPlugin . '/images/objects/legacy-icon.png'), 'sized legacy icon is staged into managed library');
+
+			unlink($repairPlugin . '/images/backgrounds/legacy-background.png'); unlink($repairPlugin . '/images/objects/legacy-icon.png');
+			file_put_contents($fixtureConfig, $legacyFixture); $GLOBALS['config_fault'] = 'rename'; weathermap_repair_maps();
+			atomic_assert(file_get_contents($fixtureConfig) === $legacyFixture && is_file($repairPlugin . '/legacy-background.png') && is_file($repairPlugin . '/legacy-icon.png'), 'failed background and icon staging preserves usable original references');
+			$GLOBALS['config_fault'] = ''; file_put_contents($fixtureConfig, "BACKGROUND absent-background.png\nNODE Missing\n ICON absent-icon.png\n");
+			$missingFixture = file_get_contents($fixtureConfig); weathermap_repair_maps();
+			atomic_assert(file_get_contents($fixtureConfig) === $missingFixture, 'missing assets do not change config paths');
+		} finally {
+			$GLOBALS['config'] = $oldConfig; $GLOBALS['weathermap_error_suppress'] = $oldSuppress; $GLOBALS['config_fault'] = '';
+			unset($GLOBALS['__test_db_fetch_assoc']); chdir($plugin);
+			$iterator = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($repairRoot, \FilesystemIterator::SKIP_DOTS), \RecursiveIteratorIterator::CHILD_FIRST);
+			foreach ($iterator as $entry) { if ($entry->isDir() && !$entry->isLink()) rmdir($entry->getPathname()); else unlink($entry->getPathname()); }
+			rmdir($repairRoot);
+		}
+		$management = file_get_contents($plugin . '/weathermap-cacti-plugin-mgmt.php');
+		$start = strpos($management, 'function newMap(');
+		eval(str_replace(['__DIR__', 'function newMap('], [var_export($plugin, true), 'function wm_management_newMap('], substr($management, $start)));
+		$GLOBALS['weathermap_confdir'] = $dir;
+		foreach (['', 'map.conf'] as $source) {
+			$destination = $dir . '/management-create.conf';
+			$GLOBALS['config_before_lock'] = function() use ($destination) { file_put_contents($destination, 'Concurrent creator'); unset($GLOBALS['config_before_lock']); };
+			wm_management_newMap('management-create.conf', $source);
+			atomic_assert(file_get_contents($destination) === 'Concurrent creator', 'management create-only preserves concurrent destination');
+			unlink($destination);
+		}
+
+		if (!function_exists('db_fetch_insert_id')) { function db_fetch_insert_id() { return 1; } }
+		// A read-only configs directory with no provisioned mutex still permits registration.
+		foreach (['add_config', 'wmap_get_title', 'map_resort'] as $functionName) {
+			$start = strpos($management, 'function ' . $functionName . '('); $end = strpos($management, "\n/**", $start);
+			eval(str_replace('__DIR__', var_export($plugin, true), substr($management, $start, $end - $start)));
+		}
+		$readonly = $dir . '/readonly'; mkdir($readonly); file_put_contents($readonly . '/map.conf', "TITLE Readonly\n");
+		chmod($readonly, 0555); $GLOBALS['weathermap_confdir'] = realpath($readonly); $GLOBALS['__test_db_calls'] = [];
+		try {
+			add_config($readonly . '/map.conf');
+			atomic_assert(cacti_count(array_filter($GLOBALS['__test_db_calls'], fn ($call) => str_contains($call['sql'], 'INSERT INTO weathermap_maps'))) === 1, 'read-only config registered without a directory lock file');
+		} finally { chdir($plugin); chmod($readonly, 0755); unlink($readonly . '/map.conf'); if (is_file($readonly . '/.weathermap-config.lock')) unlink($readonly . '/.weathermap-config.lock'); rmdir($readonly); }
+		$GLOBALS['weathermap_confdir'] = $dir;
+		foreach (['newmap', 'newmapcopy'] as $createAction) {
+			$destination = $dir . '/failed-editor-create.conf';
+			$GLOBALS['__test_request']['sourcemap'] = basename($file); $GLOBALS['__test_nfilter_request'] = ['sourcemap' => basename($file)]; $GLOBALS['mapdir'] = $dir;
+			$GLOBALS['config_fault'] = 'rename'; http_response_code(200);
+			$controller = file_get_contents($plugin . '/weathermap-cacti-plugin-editor.php'); $start = strpos($controller, "case '" . $createAction . "':"); $colon = strpos($controller, ':', $start); $end = strpos($controller, "case '", $colon);
+			$dispatch = substr($controller, $colon + 1, $end - $colon - 1); $mapfile = $destination; $terminated = false;
+			ob_start(); try { eval('switch (true) { case true:' . str_replace('exit();', 'throw new \\RuntimeException("create-finished");', $dispatch) . '}'); } catch (\RuntimeException $error) { $terminated = $error->getMessage() === 'create-finished'; } $message = ob_get_clean();
+			atomic_assert($terminated && http_response_code() === 500 && !is_file($destination) && str_contains($message, 'Please try again'), 'failed create stops controller with save status and guidance');
+			$GLOBALS['config_fault'] = ''; unset($GLOBALS['__test_request']['sourcemap']);
+		}
+		$start = strpos($management, 'function map_get_next_name('); $end = strpos($management, "\n/**", $start);
+		eval(str_replace('__DIR__', var_export($plugin, true), substr($management, $start, $end - $start)));
+		$start = strpos($management, 'function map_duplicate('); $end = strpos($management, "\n/**", $start);
+		eval(str_replace('__DIR__', var_export($plugin, true), substr($management, $start, $end - $start)));
+		$duplicateSource = 'atomic-duplicate-' . bin2hex(random_bytes(4)) . '.conf';
+		file_put_contents($plugin . '/configs/' . $duplicateSource, "TITLE Source\n");
+		$GLOBALS['__test_db_fetch_row_prepared'] = fn () => ['configfile' => $duplicateSource, 'titlecache' => 'Source', 'group_id' => 1, 'active' => 'on', 'thumb_height' => 10, 'thumb_width' => 10, 'schedule' => '', 'archiving' => '',];
+		$GLOBALS['__test_db_calls'] = []; $GLOBALS['atomic_sql_saves'] = [];
+		$GLOBALS['__test_db_fetch_cell'] = fn () => 0;
+		$GLOBALS['__test_sql_save'] = function($record) { $GLOBALS['atomic_sql_saves'][] = $record; return 1; }; $GLOBALS['config_fault'] = 'rename';
+		try {
+			map_duplicate(1, 'Clone', 'clone');
+			atomic_assert($GLOBALS['__test_db_calls'] === [] && $GLOBALS['atomic_sql_saves'] === [], 'failed clone never registers auth or settings or invokes runner');
+		} finally { unset($GLOBALS['__test_db_fetch_row_prepared'], $GLOBALS['__test_sql_save'], $GLOBALS['__test_db_fetch_cell']); unlink($plugin . '/configs/' . $duplicateSource); $GLOBALS['config_fault'] = ''; }
+		// Real raw node/link saves must not re-check their own pre-save page token.
+		$rawFile = $dir . '/raw.conf';
+		$rawConfig = "WIDTH 300\nHEIGHT 200\nNODE A\n LABEL A\n POSITION 10 10\nNODE B\n LABEL B\n POSITION 50 50\nLINK AB\n NODES A B\n";
+		foreach (['node', 'link'] as $kind) {
+			file_put_contents($rawFile, $rawConfig);
+			$GLOBALS['__test_nfilter_request'] = ['config_revision' => hash_file('sha256', $rawFile), 'node_name' => 'A', 'link_name' => 'AB', 'item_configtext' => $kind === 'node' ? "NODE A\n LABEL Updated\n POSITION 10 10\n" : "LINK AB\n NODES A B\n WIDTH 12\n"];
+			http_response_code(200); if ($kind === 'node') setNodeConfig($rawFile); else setLinkConfig($rawFile);
+			atomic_assert(http_response_code() === 200 && file_get_contents($rawFile) !== $rawConfig, 'raw ' . $kind . ' edit saves without false conflict');
+			file_put_contents($rawFile, $rawConfig); http_response_code(200);
+			$controller = file_get_contents($plugin . '/weathermap-cacti-plugin-editor.php');
+			$caseStart = strpos($controller, "case 'set_" . $kind . "_config':");
+			$caseEnd = strpos($controller, "case '", $caseStart + 5);
+			$dispatch = substr($controller, strpos($controller, ':', $caseStart) + 1, $caseEnd - strpos($controller, ':', $caseStart) - 1);
+			$mapfile = $rawFile; $terminated = false;
+			try { eval(str_replace('exit();', 'throw new \\RuntimeException("request-finished");', $dispatch)); }
+			catch (\RuntimeException $error) { if ($error->getMessage() !== 'request-finished') throw $error; $terminated = true; }
+			atomic_assert($terminated && http_response_code() === 200 && file_get_contents($rawFile) !== $rawConfig, 'controller ends successful raw ' . $kind . ' save before rendering with old token');
+
+		}
+		// All note mutations retain the 409 chosen for a save arriving after request read.
+		foreach (['move', 'delete', 'properties'] as $operation) {
+			file_put_contents($file, $original);
+			$newer = "TITLE Concurrent writer\n" . $original;
+			$GLOBALS['config_before_lock'] = function() use ($file,$newer) { unset($GLOBALS['config_before_lock']); file_put_contents($file,$newer); };
+			$GLOBALS['__test_nfilter_request'] = ['config_revision'=>hash_file('sha256',$file),'node_name'=>'note1','param'=>'note1','x'=>70,'y'=>80,'note_name'=>'note1','note_text'=>'Changed','note_font'=>'3','note_colour'=>'#000000','note_x'=>50,'note_y'=>50,'note_align'=>'left'];
+			http_response_code(200);
+			if($operation==='move')moveNode($file,0);elseif($operation==='delete')deleteNode($file);else setNoteProperties($file,0);
+			atomic_assert(http_response_code()===409 && file_get_contents($file)===$newer,'note ' . $operation . ' preserves concurrent-edit response');
+		}
+		// Registration failure must retain a mutex through the callback and remove its reservation.
+		file_put_contents($plugin . '/configs/' . $duplicateSource, "TITLE Source\n");
+		$GLOBALS['__test_db_fetch_row_prepared'] = fn () => ['configfile' => $duplicateSource, 'titlecache' => 'Source', 'group_id' => 1, 'active' => 'on', 'thumb_height' => 10, 'thumb_width' => 10, 'schedule' => '', 'archiving' => ''];
+		$GLOBALS['__test_db_fetch_cell'] = fn () => 0;
+		$GLOBALS['weathermap_confdir'] = $plugin . '/configs';
+		try {
+			foreach (['false', 'throw', 'auth-false', 'settings-false', 'auth-throw', 'settings-throw'] as $failure) {
+				$GLOBALS['__test_sql_save'] = function($record) use ($plugin, $failure) {
+					atomic_assert(is_file($plugin . '/configs/' . $record['configfile']), 'reserved file exists during registration');
+					if (function_exists('pcntl_fork')) {
+						$child = pcntl_fork();
+						if ($child === 0) { $probe = \fopen($plugin . '/configs/.weathermap-config.lock', 'rb'); exit(!\flock($probe, LOCK_EX | LOCK_NB) ? 0 : 1); }
+						pcntl_waitpid($child, $status); atomic_assert(pcntl_wexitstatus($status) === 0, 'registration retains directory mutex');
+					}
+					if ($failure === 'throw') throw new RuntimeException('registration failed');
+					return $failure === 'false' ? false : 987;
+				};
+				$GLOBALS['__test_db_calls'] = [];
+				$GLOBALS['__test_db_execute_prepared'] = function($sql, $params) use ($failure) {
+					$GLOBALS['__test_db_calls'][] = ['sql' => $sql, 'params' => $params];
+					if (str_starts_with($sql,'INSERT')) atomic_assert(!str_contains($sql, '987') && $params === [987,1], 'clone IDs are bound as prepared parameters');
+					if ((str_contains($sql, 'INSERT INTO weathermap_auth') && $failure === 'auth-throw') || (str_contains($sql, 'INSERT INTO weathermap_settings') && $failure === 'settings-throw')) throw new RuntimeException('insert failed');
+					return !((str_contains($sql, 'INSERT INTO weathermap_auth') && $failure === 'auth-false') || (str_contains($sql, 'INSERT INTO weathermap_settings') && $failure === 'settings-false'));
+				};
+				map_duplicate(1, 'Clone', 'clone');
+				atomic_assert(!is_file($plugin . '/configs/clone.conf'), 'failed registration removes its own reserved configuration');
+				if (str_ends_with($failure, '-false') || str_ends_with($failure, '-throw')) atomic_assert(cacti_count(array_filter($GLOBALS['__test_db_calls'], fn ($call) => str_starts_with($call['sql'], 'DELETE'))) === 3, 'partial registration removes map/auth/settings records');
+			}
+		} finally { unset($GLOBALS['__test_db_fetch_row_prepared'], $GLOBALS['__test_sql_save'], $GLOBALS['__test_db_fetch_cell'], $GLOBALS['__test_db_execute_prepared']); unlink($plugin . '/configs/' . $duplicateSource); }
+		$deletedMap = new \WeatherMap; $deletedMap->ReadConfig($file);
+		unlink($file);
+		atomic_assert(!$deletedMap->WriteConfig($file) && !file_exists($file), 'saving a previously loaded deleted map fails without resurrection');
+		file_put_contents($file, $original);
+		$GLOBALS['config_fault'] = 'rename';
+		$map = new \WeatherMap; $map->ReadConfig($file); $map->title = 'Changed';
+		atomic_assert(!$map->WriteConfig($file) && file_get_contents($file) === $original, 'engine failure preserves original');
+		$GLOBALS['__test_nfilter_request'] = ['map_title' => 'Failed title', 'map_legend' => 'Traffic', 'map_stamp' => 'Created', 'map_width' => 600, 'map_height' => 300, 'map_bgfile' => '--NONE--', 'map_linkdefaultwidth' => 7, 'map_linkdefaultbwin' => '100M', 'map_linkdefaultbwout' => '100M'];
+		$GLOBALS['__test_db_calls'] = [];
+		http_response_code(200); setMapProperties($file);
+		atomic_assert(http_response_code() === 500 && $GLOBALS['__test_db_calls'] === [], 'failed properties save cannot change titlecache');
+		$GLOBALS['config_fault'] = ''; http_response_code(200); setMapProperties($file);
+		atomic_assert(http_response_code() === 200 && cacti_count($GLOBALS['__test_db_calls']) === 1, 'successful properties save updates titlecache');
+		file_put_contents($file, $original); $GLOBALS['config_fault'] = 'rename';
+		$GLOBALS['__test_nfilter_request'] = ['node_name' => 'note1', 'param' => 'note1', 'x' => '70', 'y' => '80'];
+		{
+			http_response_code(200); moveNode($file, 0);
+			atomic_assert(http_response_code() === 500 && file_get_contents($file) === $original, 'failed move surfaces error without changing file');
+			http_response_code(200); deleteNode($file);
+			atomic_assert(http_response_code() === 500 && file_get_contents($file) === $original, 'failed delete surfaces error without changing file');
+		}
+		$GLOBALS['config_fault'] = '';
+		$GLOBALS['__test_nfilter_request'] = ['node_name' => 'missing', 'param' => 'missing', 'x' => '70', 'y' => '80'];
+		http_response_code(200); moveNode($file, 0);
+		atomic_assert(http_response_code() === 404 && file_get_contents($file) === $original, 'missing move target is an error');
+		http_response_code(200); deleteNode($file);
+		atomic_assert(http_response_code() === 404 && file_get_contents($file) === $original, 'missing delete target is an error');
+		unlink($file); http_response_code(200); moveNode($file, 0);
+		atomic_assert(http_response_code() === 404 && !file_exists($file), 'deleted map cannot report a successful edit');
+		echo "Atomic configuration write and locking regression PASS\n";
+	} finally {
+		$GLOBALS['config_fault'] = '';
+		foreach (glob($dir . '/*') as $path) unlink($path);
+		foreach (glob($dir . '/.wm-config-*') as $path) unlink($path);
+		if (is_file($dir . '/.weathermap-config.lock')) unlink($dir . '/.weathermap-config.lock');
+		rmdir($dir);
+	}
+}
diff --git a/tests/Support/EditorNotesEngineRegression.php b/tests/Support/EditorNotesEngineRegression.php
new file mode 100644
index 0000000..31e2a83
--- /dev/null
+++ b/tests/Support/EditorNotesEngineRegression.php
@@ -0,0 +1,238 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+
+require dirname(__DIR__) . '/bootstrap-unit.php';
+$plugin = dirname(__DIR__, 2);
+chdir($plugin);
+require $plugin . '/setup.php';
+require $plugin . '/lib/WeatherMap.class.php';
+require $plugin . '/lib/editor.inc.php';
+require $plugin . '/lib/editor.actions.php';
+function note_assert($value, $message) {
+	if (!$value) throw new RuntimeException($message);
+}
+$directory = sys_get_temp_dir() . '/wm-note-' . bin2hex(random_bytes(6));
+mkdir($directory);
+try {
+	$map = new WeatherMap;
+	$map->width = 600;
+	$map->height = 300;
+	$file = $directory . '/note.conf';
+	$map->WriteConfig($file);
+	$map->ReadConfig($file);
+
+	$background = $directory . '/large-background.png'; $bitmap = imagecreatetruecolor(200, 100); imagepng($bitmap, $background); imagedestroy($bitmap);
+	$sized = new WeatherMap; $sized->width = 120; $sized->height = 120; $sized->background = $background; $sized->add_hint('background_sizing', 'image');
+	note_assert(wm_note_effective_dimensions($sized) === [200, 100] && $sized->width === 120 && $sized->height === 120, 'background dimensions are effective while configured dimensions remain unchanged');
+	$backgroundValues = ['name' => '', 'text' => 'Inside background', 'font' => '3', 'colour' => '#000000', 'x' => 150, 'y' => 80];
+	note_assert(wm_editor_save_note($sized, $backgroundValues), 'note fits effective background beyond configured width');
+	$backgroundValues['x'] = 201; note_assert(!wm_editor_save_note($sized, $backgroundValues), 'note outside effective background is rejected');
+	$originalImap = $sized->imap; $originalAreas = serialize($originalImap);
+	wm_note_effective_dimensions($sized); wm_note_effective_dimensions($sized);
+	note_assert($sized->imap === $originalImap && serialize($sized->imap) === $originalAreas, 'repeated dimension previews preserve original clickable regions');
+	class DimensionPostProcessor extends WeatherMapPostProcessor { function run(&$map) { $map->width = 240; $map->height = 90; } }
+	$sized->background = ''; $sized->plugins['post']['DimensionPostProcessor'] = new DimensionPostProcessor; $sized->postprocessclasses = ['DimensionPostProcessor'];
+	note_assert(wm_note_effective_dimensions($sized) === [240, 90] && $sized->width === 120, 'postprocessor dimensions are reflected without changing original map');
+	$controller = file_get_contents($plugin . '/weathermap-cacti-plugin-editor.php');
+	$start = strpos($controller, "<input id='xycapture'"); $end = strpos($controller, "<input id='x'", $start); $markup = substr($controller, $start, $end - $start);
+	$editor_width = 200; $editor_height = 100; $imageurl = 'fixture.png'; ob_start(); eval('?>' . $markup); $renderedElements = ob_get_clean();
+	note_assert(substr_count($renderedElements, "width='200'") === 4 && substr_count($renderedElements, "height='100'") === 4, 'editor image attributes and data coordinates use effective logical size');
+	$values = ['name' => '', 'text' => "Main site\n10.0.0.0/24", 'font' => 'bundled:Vera.ttf:11', 'colour' => '#0000ff', 'x' => '155', 'y' => '80'];
+	note_assert(wm_editor_save_note($map, $values), 'create');
+	$name = array_keys(wm_editor_note_data($map))[0];
+	$validFont = $map->nodes[$name]->labelfont;
+	$map->nodes[$name]->labelfont = 999999;
+	set_error_handler(function($severity, $message) { throw new RuntimeException($message); });
+	try {
+		note_assert(wm_editor_note_data($map)[$name]['font'] === '3', 'missing note font falls back to a built-in');
+	} finally { restore_error_handler(); }
+	$map->nodes[$name]->labelfont = $validFont;
+	$validFile = $map->fonts[$validFont]->file;
+	$map->fonts[$validFont]->file = '/nonexistent/note-font.ttf';
+	note_assert(wm_editor_note_data($map)[$name]['font'] === '3', 'unreadable TrueType font falls back');
+	$map->fonts[$validFont]->file = $validFile;
+	note_assert(in_array($map->nodes[$name], $map->seen_zlayers[$map->nodes[$name]->zorder], true), 'new note indexed immediately');
+	$map->DrawMap($directory . '/immediate.png');
+	note_assert(getimagesize($directory . '/immediate.png')[0] === 1200, 'new note renders sharply without rereading');
+	$live = new DOMDocument;
+	$live->loadHTML(wm_liveview_image_html($map, '123'));
+	$liveImage = $live->getElementsByTagName('img')->item(0);
+	note_assert($liveImage->getAttribute('width') === '600' && $liveImage->getAttribute('height') === '300', 'live view constrains high-density image to logical dimensions');
+	note_assert($liveImage->getAttribute('src') === '?action=liveviewimage&id=123', 'live-view image endpoint retained');
+	$map->WriteConfig($file);
+	$saved = new WeatherMap;
+	$saved->ReadConfig($file);
+	$node = $saved->nodes[$name];
+	note_assert($node->label === 'Main site\\n10.0.0.0/24', 'multiline config roundtrip');
+	note_assert($node->get_hint('editor_note', '0') === '1', 'marker');
+	note_assert($node->labelfontcolour == [0,0,255] && $node->iconfile === '', 'style');
+	note_assert($node->labelbgcolour == [-1,-1,-1] && $node->labeloutlinecolour == [-1,-1,-1], 'plain text');
+	$saved->DrawMap($directory . '/note.png');
+	note_assert(is_file($directory . '/note.png'), 'render');
+
+	$size = getimagesize($directory . '/note.png');
+	note_assert($size[0] === 1200 && $size[1] === 600, 'generated viewer image double density');
+	note_assert(!$node->render_note_hidpi, 'render flag reset');
+	$saved->DrawMap($directory . '/note.png', $directory . '/thumb.png', 250);
+	$thumbSize = getimagesize($directory . '/thumb.png');
+	note_assert($thumbSize[0] === 250 && $thumbSize[1] === 125, 'thumbnail logical aspect ratio');
+	$sharpBounds = $node->boundingboxes;
+	$saved->DrawMap('null');
+	note_assert(end($node->boundingboxes) == end($sharpBounds), 'clickable note bounds remain logical');
+	note_assert(imagesx($saved->image) === 600, 'HTML-only rendering keeps logical dimensions');
+	$saved->imageuri = 'note.png';
+	note_assert(str_contains($saved->MakeHTML(), "width='600' height='300'"), 'viewer display size remains logical');
+
+	$literal = "C:\\new site\nD:\\nested\\notes\\\\share";
+	$literalValues = $values;
+	$literalValues['name'] = $name;
+	$literalValues['text'] = $literal;
+	note_assert(wm_editor_save_note($saved, $literalValues), 'save literal backslashes');
+	note_assert($saved->WriteConfig($file), 'persist escaped note');
+	$literalReload = new WeatherMap;
+	$literalReload->ReadConfig($file);
+	$literalNode = $literalReload->nodes[$name];
+	note_assert(wm_editor_note_data($literalReload)[$name]['text'] === $literal, 'dialog text preserves literal backslashes and real newlines');
+	note_assert($literalReload->ProcessString($literalNode->label, $literalNode, true, true) === $literal, 'render text preserves literal backslashes and real newlines');
+	$literalReload->DrawMap($directory . '/literal.png');
+	note_assert(is_file($directory . '/literal.png'), 'escaped note renders through high-density path');
+	$legacy = new WeatherMapNode;
+	$legacy->name = 'legacy'; $legacy->Reset($literalReload); $legacy->label = 'Old\nNote';
+	note_assert($literalReload->ProcessString($legacy->label, $legacy, true, true) === "Old\nNote", 'legacy multiline semantics retained');
+	$oldWidth = $saved->width;
+	$saved->width = 50000;
+	note_assert(wm_sharp_notes($saved) === [], 'large map allocation bounded');
+	$saved->width = $oldWidth;
+	$node->zorder = 1001;
+	note_assert(wm_sharp_notes($saved) === [], 'non-front annotation keeps original layering');
+	$node->zorder = 600;
+
+
+	$later = clone $node;
+	$later->name = 'later_node';
+	$later->label = 'Ordinary node';
+	$later->add_hint('editor_note', '0');
+	$later->x = 500;
+	$later->y = 250;
+	$saved->nodes[$later->name] = $later;
+	$later->zorder = 700;
+	$saved->seen_zlayers[700][] = $later;
+	$saved->DrawMap($directory . '/later.png');
+	note_assert(getimagesize($directory . '/later.png')[0] === 1200, 'unrelated later node keeps note sharp');
+	$later->x = $node->x;
+	$later->y = $node->y;
+	$saved->DrawMap($directory . '/overlap.png');
+	note_assert(getimagesize($directory . '/overlap.png')[0] === 600, 'overlapping later node preserves stacking');
+	array_pop($saved->seen_zlayers[700]);
+	unset($saved->nodes[$later->name]);
+
+	// Furniture is composed once, and a node above it must retain its z-order.
+	$previousTitle = $saved->title;
+	$saved->title = 'MMMMMMMMMMMMMMMM'; $saved->titlex = 450; $saved->titley = 225;
+	$saved->titlefont = $node->labelfont;
+	$node->add_hint('editor_note', '0'); $saved->DrawMap($directory . '/furniture-reference.png');
+	$node->add_hint('editor_note', '1'); $saved->DrawMap($directory . '/furniture-sharp.png');
+	$reference = imagecreatefrompng($directory . '/furniture-reference.png');
+	$expected = imagecreatetruecolor(1200, 600); imagecopyresampled($expected, $reference, 0, 0, 0, 0, 1200, 600, 600, 300);
+	$actual = imagecreatefrompng($directory . '/furniture-sharp.png');
+	$maxDifference = 0;
+	for ($x = 900; $x < 1180; $x++) for ($y = 405; $y < 455; $y++) {
+		$left = imagecolorat($expected, $x, $y); $right = imagecolorat($actual, $x, $y);
+		foreach ([0,8,16] as $shift) $maxDifference = max($maxDifference, abs((($left >> $shift) & 255) - (($right >> $shift) & 255)));
+	}
+	note_assert($maxDifference <= 2, 'furniture antialiasing is not composited twice');
+	imagedestroy($reference); imagedestroy($expected); imagedestroy($actual);
+	$foreground = clone $node; $foreground->name = 'foreground'; $foreground->label = 'Foreground';
+	$foreground->x = 500; $foreground->y = 225; $foreground->zorder = 1001; $foreground->add_hint('editor_note', '0');
+	$foreground->labelfont = 5; $foreground->labelfontcolour = [255,0,0]; $foreground->labelbgcolour = [255,0,0]; $foreground->labeloutlinecolour = [255,0,0];
+	$saved->nodes['foreground'] = $foreground; $saved->seen_zlayers[1001][] = $foreground;
+	$saved->DrawMap($directory . '/foreground.png'); $actual = imagecreatefrompng($directory . '/foreground.png');
+	for ($x = 990; $x <= 1010; $x++) for ($y = 442; $y <= 450; $y++) note_assert((imagecolorat($actual, $x, $y) & 0xffffff) === 0xff0000, 'higher node stays above title furniture');
+	imagedestroy($actual); unset($saved->nodes['foreground'], $saved->seen_zlayers[1001]); $saved->title = $previousTitle;
+	wm_comment_resolve_font($saved, 'bundled:Vera.ttf:9');
+	$fontOptions = wm_style_font_options($saved, 3);
+	note_assert(preg_match('/<option value="[0-9]+" data-wm-note-default="1"/', $fontOptions) === 1, 'registered Vera 9 exposes a stable default marker');
+
+	$hashes = [];
+	foreach (['left', 'centre', 'right'] as $alignment) {
+		$aligned = $values;
+		$aligned['name'] = $name;
+		$aligned['align'] = $alignment;
+		note_assert(wm_editor_save_note($saved, $aligned), 'save ' . $alignment);
+		$saved->WriteConfig($file);
+		$rendered = new WeatherMap;
+		$rendered->ReadConfig($file);
+		note_assert(wm_editor_note_data($rendered)[$name]['align'] === $alignment, 'alignment roundtrip');
+		$png = $directory . '/' . $alignment . '.png';
+		$rendered->DrawMap($png);
+		$hashes[] = hash_file('sha256', $png);
+	}
+	note_assert(cacti_count(array_unique($hashes)) === 3, 'alignments change rendered pixels');
+	$values['name'] = $name;
+	$values['text'] = 'Edited note';
+	$values['colour'] = '#c00000';
+	$values['x'] = '205';
+	note_assert(wm_editor_save_note($saved, $values), 'edit');
+	$saved->WriteConfig($file);
+	$again = new WeatherMap;
+	$again->ReadConfig($file);
+	note_assert($again->nodes[$name]->label === 'Edited note' && $again->nodes[$name]->x == 205, 'edit persists');
+	foreach (['text' => "bad\nNODE injected", 'name' => 'DEFAULT', 'font' => '../../bad.ttf', 'colour' => '#nope', 'x' => '-1', 'y' => '301', 'align' => 'invalid'] as $key => $value) {
+		$bad = $values; $bad[$key] = $value;
+		if ($key === 'text') {
+			note_assert(wm_editor_save_note($again, $bad), 'newline stays text');
+			$again->WriteConfig($file);
+			note_assert(strpos(file_get_contents($file), "\nNODE injected") === false, 'no config injection');
+		} else note_assert(!wm_editor_save_note($again, $bad), 'reject ' . $key);
+	}
+	$GLOBALS['__test_nfilter_request'] = ['param' => $name];
+	deleteNode($file);
+	$deleted = new WeatherMap;
+	$deleted->ReadConfig($file);
+	note_assert(!isset($deleted->nodes[$name]), 'delete persists');
+	$templateFile = $directory . '/templates.conf';
+	file_put_contents($templateFile, "NODE templateNode\n LABEL Template\nNODE A\n POSITION 10 10\nNODE B\n POSITION 50 50\nLINK templateLink\n WIDTH 8\nLINK trafficLink\n NODES A B\n");
+	$templateMap = new WeatherMap;
+	note_assert($templateMap->ReadConfig($templateFile), 'read templates and real link');
+	note_assert($templateMap->WriteConfig($templateFile), 'write templates and real link');
+	$reloadedTemplates = new WeatherMap;
+	$reloadedTemplates->ReadConfig($templateFile);
+	note_assert(isset($reloadedTemplates->nodes['templateNode'], $reloadedTemplates->links['templateLink'], $reloadedTemplates->links['trafficLink']), 'write retains template nodes and template/real links');
+	class NoteFailingWriteStream {
+		public $context;
+		public function url_stat($path, $flags) { return ['mode' => 0100777]; }
+		public function stream_open($path, $mode, $options, &$opened) { return true; }
+		public function stream_write($data) { return 0; }
+		public function stream_flush() { return false; }
+		public function stream_close() {}
+	}
+	stream_wrapper_register('notewritefail', NoteFailingWriteStream::class);
+	try { note_assert($map->WriteConfig('notewritefail://map/config') === false, 'write and flush failures propagate'); }
+	finally { stream_wrapper_unregister('notewritefail'); }
+	print "PASS: note create, render, edit, styles, multiline, validation and delete\n";
+} finally {
+	foreach (glob($directory . '/*') as $file) unlink($file);
+	if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
+	rmdir($directory);
+}
diff --git a/tests/Support/GalleryPreviewRender.php b/tests/Support/GalleryPreviewRender.php
index 467a208..553e8a9 100644
--- a/tests/Support/GalleryPreviewRender.php
+++ b/tests/Support/GalleryPreviewRender.php
@@ -143,5 +143,6 @@ function weathermap_tabs($group) {
 		unlink($file);
 	}
 	rmdir($directory . '/output');
+	if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
 	rmdir($directory);
 }
diff --git a/tests/Support/MapDuplicatePayload.php b/tests/Support/MapDuplicatePayload.php
index ad558dd..3e6dce8 100644
--- a/tests/Support/MapDuplicatePayload.php
+++ b/tests/Support/MapDuplicatePayload.php
@@ -14,7 +14,11 @@
 if ($start === false || $end === false) {
 	throw new RuntimeException('Unable to locate the map duplication function.');
 }
-eval(substr($source, $start, $end - $start));
+$fixture = sys_get_temp_dir() . '/wm-duplicate-' . bin2hex(random_bytes(5));
+mkdir($fixture); mkdir($fixture . '/configs');
+symlink(dirname(__DIR__, 2) . '/lib', $fixture . '/lib');
+file_put_contents($fixture . '/configs/Original.conf', "TITLE Original Map\n");
+eval(str_replace('__DIR__', var_export($fixture, true), substr($source, $start, $end - $start)));
 
 /**
  * Return the source map fixture.
@@ -92,5 +96,16 @@ function sql_save($payload, $table) {
 	return 0;
 }
 
-map_duplicate(5, '<map_title> Copy');
-print json_encode($GLOBALS['duplicate_save'], JSON_THROW_ON_ERROR);
+/** Ignore expected registration failure notices in this schema-only fixture. */
+function raise_message($id, $text = '', $level = 0) {}
+/** Return the untranslated fixture string. */
+function __($text, ...$args) { return $text; }
+define('MESSAGE_LEVEL_ERROR', 3);
+try {
+	map_duplicate(5, '<map_title> Copy');
+	print json_encode($GLOBALS['duplicate_save'], JSON_THROW_ON_ERROR);
+} finally {
+	foreach (glob($fixture . '/configs/*') as $file) unlink($file);
+	if (is_file($fixture . '/configs/.weathermap-config.lock')) unlink($fixture . '/configs/.weathermap-config.lock');
+	unlink($fixture . '/lib'); rmdir($fixture . '/configs'); rmdir($fixture);
+}
diff --git a/tests/Support/NewMapPresetEngineRegression.php b/tests/Support/NewMapPresetEngineRegression.php
index 6323b6e..d738d43 100644
--- a/tests/Support/NewMapPresetEngineRegression.php
+++ b/tests/Support/NewMapPresetEngineRegression.php
@@ -86,5 +86,7 @@ function wm_engine_assert($value,$message) {
 } finally {
 	foreach (glob($directory . '/*') as $file) {
 		unlink($file);
-	}rmdir($directory);
+	}
+	if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
+	rmdir($directory);
 }
diff --git a/tests/Support/NewMapTitleEngineRegression.php b/tests/Support/NewMapTitleEngineRegression.php
index 636f6d7..3410b65 100644
--- a/tests/Support/NewMapTitleEngineRegression.php
+++ b/tests/Support/NewMapTitleEngineRegression.php
@@ -112,5 +112,7 @@ function wm_engine_assert($value,$message) {
 } finally {
 	foreach (glob($directory . '/*') as $file) {
 		unlink($file);
-	}rmdir($directory);
+	}
+	if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
+	rmdir($directory);
 }
diff --git a/tests/Support/NoteAllocationRegression.php b/tests/Support/NoteAllocationRegression.php
new file mode 100644
index 0000000..f01c256
--- /dev/null
+++ b/tests/Support/NoteAllocationRegression.php
@@ -0,0 +1,92 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+
+namespace WeathermapNotes {
+	/**
+	 * Simulate an unavailable note canvas in an isolated rendering process.
+	 *
+	 * @param int $width Canvas width.
+	 * @param int $height Canvas height.
+	 * @return \GdImage|false
+	 */
+	function imagecreatetruecolor($width, $height) {
+		$GLOBALS['note_allocations']++;
+		if ($GLOBALS['note_allocations'] === ($GLOBALS['note_fail_at'] ?? 0)) return false;
+		if (($GLOBALS['note_fail_at'] ?? 0) === -1) throw new \ValueError('allocation unavailable');
+		return \imagecreatetruecolor($width, $height);
+	}
+}
+namespace {
+	require dirname(__DIR__) . '/bootstrap-unit.php';
+	chdir(dirname(__DIR__, 2));
+	require 'setup.php'; require 'lib/WeatherMap.class.php';
+	$dir = sys_get_temp_dir() . '/wm-note-allocation-' . bin2hex(random_bytes(4)); mkdir($dir);
+	try {
+		$file = $dir . '/map.conf';
+		file_put_contents($file, "WIDTH 400\nHEIGHT 200\nFONTDEFINE 100 docs/example/Vera.ttf 9\nNODE label\n LABEL Readable note\n LABELFONT 100\n LABELBGCOLOR none\n LABELOUTLINECOLOR none\n LABELFONTSHADOWCOLOR none\n POSITION 150 100\n SET editor_note 1\n");
+		foreach ([1, 2, 0] as $failure) {
+			$GLOBALS['note_allocations'] = 0; $GLOBALS['note_fail_at'] = $failure;
+			$map = new \WeatherMap; $map->ReadConfig($file); $map->stamptext = '';
+			$output = $dir . '/render-' . $failure . '.png'; $map->DrawMap($output);
+			if (getimagesize($output)[0] !== ($failure ? 400 : 800)) throw new \RuntimeException('allocation fallback dimensions');
+			$image = imagecreatefrompng($output); $ink = 0; $scale = $failure ? 1 : 2;
+			for ($x = 110 * $scale; $x < 190 * $scale; $x++) {
+				for ($y = 90 * $scale; $y < 110 * $scale; $y++) if ((imagecolorat($image, $x, $y) & 0xffffff) === 0) $ink++;
+			}
+			if (!$ink) throw new \RuntimeException('fallback must retain readable note glyphs');
+			imagedestroy($image);
+		}
+		require_once 'lib/editor.inc.php'; require_once 'lib/editor.notes.php';
+		foreach (['missing', 'invalid', 'unreadable', 'truncated'] as $fontCase) {
+			$GLOBALS['note_allocations'] = 0; $GLOBALS['note_fail_at'] = 0;
+			$map = new \WeatherMap; $map->ReadConfig($file); $map->stamptext = '';
+			$fontPath = $dir . '/font-' . $fontCase . '.ttf';
+			if ($fontCase === 'invalid') file_put_contents($fontPath, 'invalid font');
+			if ($fontCase === 'truncated') file_put_contents($fontPath, "\x00\x01\x00\x00" . str_repeat("\0", 20));
+			if ($fontCase === 'unreadable') { copy('docs/example/Vera.ttf', $fontPath); chmod($fontPath, 0000); if (is_readable($fontPath)) { chmod($fontPath, 0600); continue; } }
+			$map->fonts[100]->file = $fontPath;
+			$output = $dir . '/fallback-' . $fontCase . '.png'; $map->DrawMap($output);
+			if ($map->nodes['label']->labelfont !== 3 || getimagesize($output)[0] !== 400) throw new \RuntimeException('loaded invalid font must fall back before drawing');
+			$image = imagecreatefrompng($output); $ink = 0;
+			for ($x = 95; $x < 205; $x++) for ($y = 85; $y < 115; $y++) if ((imagecolorat($image, $x, $y) & 0xffffff) === 0) $ink++;
+			if (!$ink) throw new \RuntimeException('invalid loaded font must retain readable glyphs'); imagedestroy($image);
+			$values = ['name'=>'label','text'=>'Saved fallback','font'=>'100','colour'=>'#000000','x'=>150,'y'=>100,'align'=>'left'];
+			if (!wm_editor_save_note($map,$values,0) || $map->nodes['label']->labelfont !== 3) throw new \RuntimeException('submitted invalid registered font must fall back');
+			if ($fontCase === 'unreadable') chmod($fontPath,0600);
+		}
+		$values['font'] = '99999';
+		if (!wm_editor_save_note($map, $values, 0) || $map->nodes['label']->labelfont !== 3) throw new \RuntimeException('unavailable submitted numeric font falls back');
+		$values['font'] = '../bad.ttf';
+		if (wm_editor_save_note($map, $values, 0)) throw new \RuntimeException('path-like font still rejected');
+		if (wm_note_font_id($map,99999)!==3) throw new \RuntimeException('unknown font fallback');
+		$GLOBALS['note_allocations'] = 0; $GLOBALS['note_fail_at'] = 1;
+		if (wm_note_display_image($map, []) !== false) throw new \RuntimeException('direct display allocation failure');
+		$GLOBALS['note_fail_at'] = -1;
+		if (\WeathermapNotes\allocate(1, 1) !== false) throw new \RuntimeException('allocator exception fallback');
+		echo "Note canvas allocation fallback PASS\n";
+	} finally {
+		foreach (glob($dir . '/*') as $path) unlink($path);
+		rmdir($dir);
+	}
+}
diff --git a/tests/Support/SavedPresetFallbackRegression.php b/tests/Support/SavedPresetFallbackRegression.php
index a073874..993321d 100644
--- a/tests/Support/SavedPresetFallbackRegression.php
+++ b/tests/Support/SavedPresetFallbackRegression.php
@@ -70,5 +70,6 @@ function clean_up_name($value) {
 	foreach (glob($directory . '/*') as $file) {
 		unlink($file);
 	}
+	if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
 	rmdir($directory);
 }
diff --git a/tests/Unit/ConfigFileDeleteTest.php b/tests/Unit/ConfigFileDeleteTest.php
index 57ab72b..e4a2a24 100644
--- a/tests/Unit/ConfigFileDeleteTest.php
+++ b/tests/Unit/ConfigFileDeleteTest.php
@@ -54,7 +54,9 @@
 
 		foreach (glob($dir . '/*') as $p) {
 			unlink($p);
-		}rmdir($dir);
+		}
+		if (is_file($dir . '/.weathermap-config.lock')) unlink($dir . '/.weathermap-config.lock');
+		rmdir($dir);
 	}
 });
 it('ReportsADeletionFailureWithoutClaimingSuccess', function () {
@@ -79,6 +81,7 @@
 		restore_error_handler();
 		chmod($dir,0700);
 		unlink($dir . '/test.conf');
+		if (is_file($dir . '/.weathermap-config.lock')) unlink($dir . '/.weathermap-config.lock');
 		rmdir($dir);
 		unset($GLOBALS['__test_db_fetch_cell_prepared']);
 	}
@@ -120,6 +123,7 @@
 		foreach (glob($weathermap_confdir . '/*') as $path) {
 			unlink($path);
 		}
+		if (is_file($weathermap_confdir . '/.weathermap-config.lock')) unlink($weathermap_confdir . '/.weathermap-config.lock');
 		rmdir($weathermap_confdir);
 		unset($GLOBALS['__test_nfilter_request']['file'], $GLOBALS['__test_raise_message'], $GLOBALS['__test_delete_message'], $GLOBALS['__test_db_fetch_cell_prepared']);
 
@@ -153,7 +157,9 @@
 		unset($GLOBALS['__test_db_fetch_cell_prepared'], $GLOBALS['__test_db_fetch_assoc_prepared']);
 		unlink($directory . '/Other.conf');
 		if (file_exists($directory . '/Map.conf')) { unlink($directory . '/Map.conf'); }
+		if (is_file($directory . '/sub' . '/.weathermap-config.lock')) unlink($directory . '/sub' . '/.weathermap-config.lock');
 		rmdir($directory . '/sub');
+		if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
 		rmdir($directory);
 	}
 });
diff --git a/tests/Unit/ConfigRegistrationLockTest.php b/tests/Unit/ConfigRegistrationLockTest.php
index 6c5b946..7a15701 100644
--- a/tests/Unit/ConfigRegistrationLockTest.php
+++ b/tests/Unit/ConfigRegistrationLockTest.php
@@ -101,6 +101,7 @@ function map_resort() {}
 		$weathermap_confdir = $old_directory;
 		unset($GLOBALS['__test_db_execute_prepared'], $GLOBALS['__test_db_fetch_cell_prepared']);
 		foreach (glob($directory . '/*') as $entry) { unlink($entry); }
+		if (is_file($directory . '/.weathermap-config.lock')) unlink($directory . '/.weathermap-config.lock');
 		rmdir($directory);
 	}
 });
diff --git a/tests/Unit/ConfigWriteAtomicTest.php b/tests/Unit/ConfigWriteAtomicTest.php
new file mode 100644
index 0000000..913fe48
--- /dev/null
+++ b/tests/Unit/ConfigWriteAtomicTest.php
@@ -0,0 +1,46 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+use PHPUnit\Framework\Attributes\RunInSeparateProcess;
+use PHPUnit\Framework\Attributes\PreserveGlobalState;
+use PHPUnit\Framework\TestCase;
+
+final class ConfigWriteAtomicTest extends TestCase {
+	/**
+	 * Verify real engine persistence and coordinated filesystem failures.
+	 *
+	 * @return void
+	 */
+	#[RunInSeparateProcess]
+	#[PreserveGlobalState(false)]
+	public function testRealEngineRegression(): void {
+		ob_start();
+		try {
+			require dirname(__DIR__) . '/Support/ConfigWriteAtomicRegression.php';
+			$result = ob_get_contents();
+		} finally {
+			ob_end_clean();
+		}
+		self::assertSame("Atomic configuration write and locking regression PASS\n", $result);
+	}
+}
diff --git a/tests/Unit/EditorNotesEngineTest.php b/tests/Unit/EditorNotesEngineTest.php
new file mode 100644
index 0000000..e713352
--- /dev/null
+++ b/tests/Unit/EditorNotesEngineTest.php
@@ -0,0 +1,41 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+use PHPUnit\Framework\Attributes\RunInSeparateProcess;
+use PHPUnit\Framework\Attributes\PreserveGlobalState;
+use PHPUnit\Framework\TestCase;
+
+final class EditorNotesEngineTest extends TestCase {
+	#[RunInSeparateProcess]
+	#[PreserveGlobalState(false)]
+	public function testRealEngineRegression(): void {
+		ob_start();
+		try {
+			require dirname(__DIR__) . '/Support/EditorNotesEngineRegression.php';
+			$result = ob_get_contents();
+		} finally {
+			ob_end_clean();
+		}
+		self::assertSame("PASS: note create, render, edit, styles, multiline, validation and delete\n", $result);
+	}
+}
diff --git a/tests/Unit/NoteAllocationTest.php b/tests/Unit/NoteAllocationTest.php
new file mode 100644
index 0000000..1f3734b
--- /dev/null
+++ b/tests/Unit/NoteAllocationTest.php
@@ -0,0 +1,46 @@
+<?php
+/*
+ +-------------------------------------------------------------------------+
+ | Copyright (C) 2004-2026 The Cacti Group, Howard Jones                   |
+ |                                                                         |
+ | This program is free software; you can redistribute it and/or           |
+ | modify it under the terms of the GNU General Public License             |
+ | as published by the Free Software Foundation; either version 2          |
+ | of the License, or (at your option) any later version.                  |
+ |                                                                         |
+ | This program is distributed in the hope that it will be useful,         |
+ | but WITHOUT ANY WARRANTY; without even the implied warranty of          |
+ | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           |
+ | GNU General Public License for more details.                            |
+ +-------------------------------------------------------------------------+
+ | Cacti: The Complete RRDtool-based Graphing Solution                     |
+ +-------------------------------------------------------------------------+
+ | This code is designed, written, and maintained by the Cacti Group. See  |
+ | about.php and/or the AUTHORS file for specific developer information.   |
+ +-------------------------------------------------------------------------+
+ | http://www.cacti.net/                                                   |
+ +-------------------------------------------------------------------------+
+*/
+use PHPUnit\Framework\Attributes\RunInSeparateProcess;
+use PHPUnit\Framework\Attributes\PreserveGlobalState;
+use PHPUnit\Framework\TestCase;
+
+final class NoteAllocationTest extends TestCase {
+	/**
+	 * Verify both note canvas failures retain logical rendering and glyphs.
+	 *
+	 * @return void
+	 */
+	#[RunInSeparateProcess]
+	#[PreserveGlobalState(false)]
+	public function testRealEngineRegression(): void {
+		ob_start();
+		try {
+			require dirname(__DIR__) . '/Support/NoteAllocationRegression.php';
+			$result = ob_get_contents();
+		} finally {
+			ob_end_clean();
+		}
+		self::assertSame("Note canvas allocation fallback PASS\n", $result);
+	}
+}
diff --git a/tests/Unit/WeathermapUpgradeTest.php b/tests/Unit/WeathermapUpgradeTest.php
index 6800e6a..fd63cdb 100644
--- a/tests/Unit/WeathermapUpgradeTest.php
+++ b/tests/Unit/WeathermapUpgradeTest.php
@@ -5,61 +5,68 @@
  +-------------------------------------------------------------------------+
 */
 
-/*
- * Unit coverage for plugin_weathermap_upgrade() in setup.php: the
- * page-guard.
- *
- * The rest of the function (reached on any allowed page) is intentionally
- * NOT covered here: it include_once()s lib/poller-common.php, which itself
- * include_once()s lib/WeatherMap.class.php - a file this plugin's own
- * other test suites (e.g. tests/Handoff) already load directly by a
- * different path, and loading it a second time via a different resolved
- * path fatals with "Cannot declare class WeatherMapDataSource, because
- * the name is already in use". The version-drift branch also calls
- * weathermap_repair_maps(), which does a real chdir() and reads/writes
- * map config files on disk - a much larger and riskier surface than this
- * suite stubs.
- */
-
-beforeAll(function () {
-	require_once __DIR__ . '/../../setup.php';
-});
-
-beforeEach(function () {
-	$GLOBALS['__test_db_calls']     = [];
-	$GLOBALS['__test_current_page'] = '';
-});
-
-it('does nothing on a page that does not need the version check', function () {
-	test_set_current_page('graphs.php');
+use PHPUnit\Framework\Attributes\RunTestsInSeparateProcesses;
+use PHPUnit\Framework\Attributes\PreserveGlobalState;
+use PHPUnit\Framework\TestCase;
 
-	plugin_weathermap_upgrade();
+/** Exercise upgrade dispatch without sharing production-function stubs. */
+#[RunTestsInSeparateProcesses]
+#[PreserveGlobalState(false)]
+final class WeathermapUpgradeTest extends TestCase {
+	/**
+	 * Install the upgrade-only repair stub in this isolated process.
+	 *
+	 * @return void
+	 */
+	protected function setUp(): void {
+		require_once __DIR__ . '/../../setup.php';
+		if (!function_exists('weathermap_repair_maps')) {
+			/**
+			 * Stub filesystem repair only within an isolated upgrade test.
+			 *
+			 * @return void
+			 */
+			function weathermap_repair_maps() {}
+		}
+		$GLOBALS['__test_db_calls'] = [];
+		$GLOBALS['__test_current_page'] = '';
+	}
 
-	expect($GLOBALS['__test_db_calls'])->toBeEmpty();
-});
+	/**
+	 * Verify unrelated pages do not trigger upgrade queries.
+	 *
+	 * @return void
+	 */
+	public function testUnrelatedPageSkipsUpgrade(): void {
+		test_set_current_page('graphs.php');
+		plugin_weathermap_upgrade();
+		self::assertEmpty($GLOBALS['__test_db_calls']);
+	}
 
-it('runs the realm/version updates and prune on a version drift', function () {
-test_set_current_page('plugins.php');
-
-// Sandbox base_path with an empty poller-common stub + minimal INFO so the
-// upgrade-time prune runs against a throwaway tree, never the real checkout,
-// and the heavy lib include is a no-op.
-$restore = $GLOBALS['config']['base_path'];
-$base    = sys_get_temp_dir() . '/weathermap-upg-' . uniqid();
-mkdir($base . '/plugins/weathermap/lib', 0777, true);
-file_put_contents($base . '/plugins/weathermap/lib/poller-common.php', "<?php\n");
-file_put_contents($base . '/plugins/weathermap/INFO', "[info]\nversion = 9.9.9\nname = weathermap\nlongname = Weathermap\nauthor = x\nhomepage = x\n");
-$GLOBALS['config']['base_path'] = $base;
-
-try {
-plugin_weathermap_upgrade();
-} finally {
-$GLOBALS['config']['base_path'] = $restore;
+	/**
+	 * Verify a version drift updates the realm and version metadata.
+	 *
+	 * @return void
+	 */
+	public function testVersionDriftUpdatesRealmAndVersion(): void {
+		test_set_current_page('plugins.php');
+		$restore = $GLOBALS['config']['base_path'];
+		$base = sys_get_temp_dir() . '/weathermap-upg-' . bin2hex(random_bytes(6));
+		$plugin = $base . '/plugins/weathermap';
+		mkdir($plugin . '/lib', 0777, true);
+		file_put_contents($plugin . '/lib/poller-common.php', "<?php\n");
+		file_put_contents($plugin . '/INFO', "[info]\nversion = 9.9.9\nname = weathermap\nlongname = Weathermap\nauthor = x\nhomepage = x\n");
+		$GLOBALS['config']['base_path'] = $base;
+		try {
+			plugin_weathermap_upgrade();
+			$updates = array_filter($GLOBALS['__test_db_calls'], function ($call) {
+				return $call['fn'] === 'db_execute_prepared' && stripos($call['sql'], 'UPDATE plugin_config') !== false;
+			});
+			self::assertNotEmpty($updates);
+		} finally {
+			$GLOBALS['config']['base_path'] = $restore;
+			unlink($plugin . '/INFO'); unlink($plugin . '/lib/poller-common.php');
+			rmdir($plugin . '/lib'); rmdir($plugin); rmdir($base . '/plugins'); rmdir($base);
+		}
+	}
 }
-
-$updates = array_values(array_filter($GLOBALS['__test_db_calls'], function ($call) {
-return $call['fn'] === 'db_execute_prepared' && stripos($call['sql'], 'UPDATE plugin_config') !== false;
-}));
-
-expect($updates)->not->toBeEmpty();
-});
diff --git a/tests/bootstrap-unit.php b/tests/bootstrap-unit.php
index 5e4a219..7cebba0 100644
--- a/tests/bootstrap-unit.php
+++ b/tests/bootstrap-unit.php
@@ -67,6 +67,7 @@ function db_execute_prepared($sql, $params = []) {
 
 if (!function_exists('db_fetch_assoc')) {
 	function db_fetch_assoc($sql) {
+		if (isset($GLOBALS['__test_db_fetch_assoc'])) return ($GLOBALS['__test_db_fetch_assoc'])($sql);
 		return [];
 	}
 }
@@ -103,6 +104,7 @@ function db_fetch_row_prepared($sql, $p = []) {
 
 if (!function_exists('db_fetch_cell')) {
 	function db_fetch_cell($sql) {
+		if (isset($GLOBALS['__test_db_fetch_cell'])) return ($GLOBALS['__test_db_fetch_cell'])($sql);
 		return '';
 	}
 }
@@ -184,14 +186,6 @@ function test_set_current_page($page) {
 	}
 }
 
-// Real implementation lives in lib/poller-common.php, which is never included
-// at runtime by the test suites (it pulls in WeatherMap.class.php); stub it so
-// the upgrade-path test can drive plugin_weathermap_upgrade() safely.
-if (!function_exists('weathermap_repair_maps')) {
-	function weathermap_repair_maps() {
-	}
-}
-
 if (!function_exists('isset_request_var')) {
 	function isset_request_var($n) {
 		return isset($GLOBALS['__test_request'][$n]);
@@ -346,6 +340,7 @@ function is_error_message() {
 
 if (!function_exists('sql_save')) {
 	function sql_save($a, $t, $k = 'id') {
+		if (isset($GLOBALS['__test_sql_save'])) return ($GLOBALS['__test_sql_save'])($a, $t, $k);
 		return isset($a['id']) ? $a['id'] : 1;
 	}
 }
diff --git a/weathermap-cacti-plugin-editor.php b/weathermap-cacti-plugin-editor.php
index 2e86436..af323b9 100644
--- a/weathermap-cacti-plugin-editor.php
+++ b/weathermap-cacti-plugin-editor.php
@@ -94,7 +94,7 @@
 	$action = wm_editor_sanitize_action(get_nfilter_request_var('action'), [
 		'graphs', 'datasources', 'newmap', 'newmapcopy', 'font_samples', 'draw',
 		'show_config', 'fetch_config', 'set_link_config', 'set_node_config',
-		'set_node_properties', 'set_link_properties', 'set_map_properties',
+		'set_note_properties', 'set_node_properties', 'set_link_properties', 'set_map_properties',
 		'set_map_style', 'add_link2', 'place_legend', 'place_stamp', 'via_link',
 		'move_node', 'link_tidy', 'retidy', 'retidy_all', 'untidy',
 		'delete_link', 'add_node', 'editor_settings', 'delete_node',
@@ -137,11 +137,17 @@
 		display_datasources();
 		exit;
 	case 'newmap':
-		newMap($mapfile);
+		if (!newMap($mapfile)) {
+			print __esc('Unable to save changes. Please try again.', 'weathermap');
+			exit();
+		}
 
 		break;
 	case 'newmapcopy':
-		newMapCopy($mapfile);
+		if (!newMapCopy($mapfile)) {
+			print __esc('Unable to save changes. Please try again.', 'weathermap');
+			exit();
+		}
 
 		break;
 	case 'font_samples':
@@ -163,11 +169,14 @@
 	case 'set_link_config':
 		setLinkConfig($mapfile);
 
-		break;
+		exit();
 	case 'set_node_config':
 		setNodeConfig($mapfile);
 
-		break;
+		exit();
+	case 'set_note_properties':
+		setNoteProperties($mapfile, $grid_snap_value);
+		exit;
 	case 'set_node_properties':
 		setNodeProperties($mapfile);
 		exit;
@@ -237,7 +246,8 @@
 }
 
 $map = new WeatherMap;
-$map->ReadConfig($mapfile);
+$map->context = 'editor';
+if (!wm_editor_read_config($map, $mapfile)) exit;
 
 // by here, there should be a valid $map - either a blank one, the existing one, or the existing one with requested changes
 wm_debug('Finished modifying');
@@ -246,6 +256,7 @@
 // expected.  This function should re redundant as the images are relocated during upgrade, but
 // is left here just in case.
 fixMapBackgroundAndImages($map);
+[$editor_width, $editor_height] = wm_note_effective_dimensions($map);
 
 // get the list from the images/ folder too
 $image_list   = get_imagelist('objects');
@@ -311,6 +322,7 @@
 			<li class='tb_active' id='tb_newfile'><?php print __('Change<br>File', 'weathermap'); ?></li>
 			<li class='tb_active' id='tb_addnode'><?php print __('Add<br>Node', 'weathermap'); ?></li>
 			<li class='tb_active' id='tb_addlink'><?php print __('Add<br>Link', 'weathermap'); ?></li>
+			<li class='tb_active' id='tb_addnote'><?php print __('Add<br>Note', 'weathermap'); ?></li>
 			<li class='tb_active' id='tb_poslegend'><?php print __('Position<br>Legend', 'weathermap'); ?></li>
 			<li class='tb_active' id='tb_postime'><?php print __('Position<br>Timestamp', 'weathermap'); ?></li>
 			<li class='tb_active' id='tb_mapprops'><?php print __('Map<br>Properties', 'weathermap'); ?></li>
@@ -326,8 +338,8 @@
 	</div>
 	<form id='frmMain' action='<?php print $editor_name ?>' method='post'>
 		<div class='mainArea'>
-			<input id='xycapture' name='xycapture' data-width='<?php print html_escape($map->width); ?>' data-height='<?php print html_escape($map->height); ?>' style='display:none' type='image' src='<?php print html_escape($imageurl); ?>' />
-			<img id='existingdata' name='existingdata' data-width='<?php print html_escape($map->width); ?>' data-height='<?php print html_escape($map->height); ?>' src='<?php print html_escape($imageurl); ?>' usemap='#weathermap_imap' />
+			<input id='xycapture' name='xycapture' width='<?php print html_escape($editor_width); ?>' height='<?php print html_escape($editor_height); ?>' data-width='<?php print html_escape($editor_width); ?>' data-height='<?php print html_escape($editor_height); ?>' style='display:none' type='image' src='<?php print html_escape($imageurl); ?>' />
+			<img id='existingdata' name='existingdata' width='<?php print html_escape($editor_width); ?>' height='<?php print html_escape($editor_height); ?>' data-width='<?php print html_escape($editor_width); ?>' data-height='<?php print html_escape($editor_height); ?>' src='<?php print html_escape($imageurl); ?>' usemap='#weathermap_imap' />
 			<input id='x' name='x' type='hidden' />
 			<input id='y' name='y' type='hidden' />
 			<div class='debug' style='display:none'><p><strong><?php print __('Debug', 'weathermap'); ?></strong>
@@ -363,7 +375,7 @@
 		<!-- Data for overlay and selection -->
 		<div class='scriptData'>
 			<script type='text/javascript' <?php print plugin_weathermap_csp_nonce(); ?>>
-			<?php getMapJavaScript($mapfile); ?>
+			<?php getMapJavaScript($mapfile, $map); ?>
 			<?php print 'var infoUrlStyle=' . intval(read_config_option('weathermap_infourl_style')) . ';'; ?>
 			</script>
 		</div>
@@ -372,6 +384,32 @@
 		</div>
 		<!-- End Data for overlay and selection -->
 
+
+		<div id='dlgNoteProperties' class='dlgProperties' title='<?php print __esc('Note', 'weathermap'); ?>'>
+			<div class='dlgBody'>
+				<div id='wm-note-delete-bar' style='text-align:right;margin-bottom:8px'><button type='button' id='note_delete' class='ui-button ui-corner-all' style='color:#9b2525'><?php print __esc('Delete Note', 'weathermap'); ?></button></div>
+				<input type='hidden' id='note_name' name='note_name' value='' />
+				<table class='cactiTable'>
+					<tr><td><label for='note_text'><?php print __esc('Text', 'weathermap'); ?></label></td><td><textarea id='note_text' name='note_text' rows='3' maxlength='2000' style='width:100%'></textarea></td></tr>
+					<tr><td><label for='note_align'><?php print __esc('Text alignment', 'weathermap'); ?></label></td><td><select id='note_align' name='note_align'><option value='left'><?php print __esc('Left', 'weathermap'); ?></option><option value='centre'><?php print __esc('Centre', 'weathermap'); ?></option><option value='right'><?php print __esc('Right', 'weathermap'); ?></option></select></td></tr>
+					<tr><td><label for='note_font'><?php print __esc('Font', 'weathermap'); ?></label></td><td><select id='note_font' name='note_font'><?php print wm_style_font_options($map, $map->nodes['DEFAULT']->labelfont); ?></select></td></tr>
+					<tr><td><?php print __esc('Colour', 'weathermap'); ?></td><td><div id='note_palette' role='group' aria-label='<?php print __esc('Note colour', 'weathermap'); ?>' style='display:flex;flex-wrap:wrap;gap:6px'>
+					<?php foreach (['#000000' => __esc('Black', 'weathermap'), '#0000ff' => __esc('Blue', 'weathermap'), '#cc0000' => __esc('Red', 'weathermap'), '#008000' => __esc('Green', 'weathermap'), '#800080' => __esc('Purple', 'weathermap'), '#b35900' => __esc('Orange', 'weathermap'), '#666666' => __esc('Grey', 'weathermap'), '#ffffff' => __esc('White', 'weathermap')] as $colour => $label) { ?>
+						<button type='button' class='wm-note-colour ui-button ui-corner-all' data-colour='<?php print $colour; ?>' aria-pressed='false'><span aria-hidden='true' style='display:inline-block;width:12px;height:12px;background:<?php print $colour; ?>;border:1px solid #888;margin-right:5px'></span><?php print $label; ?></button>
+					<?php } ?></div></td></tr>
+					<tr><td><?php print __esc('Position', 'weathermap'); ?></td><td><input type='text' aria-label='X' size='4' class='ui-state-default ui-corner-all' id='note_x' name='note_x' min='0' max='<?php print $editor_width; ?>' />,<input type='text' aria-label='Y' size='4' class='ui-state-default ui-corner-all' id='note_y' name='note_y' min='0' max='<?php print $editor_height; ?>' /></td></tr>
+				</table>
+				<button type='button' id='note_advanced_toggle' class='ui-button ui-corner-all' aria-expanded='false' aria-controls='note_advanced'><?php print __esc('Advanced settings', 'weathermap'); ?></button><div id='note_advanced' style='display:none'><p><label for='note_colour'><?php print __esc('Custom colour', 'weathermap'); ?></label> <input type='color' id='note_colour' name='note_colour' value='#000000' /></p></div>
+				<p id='wm-note-error' role='alert' style='display:none'></p>
+			</div>
+			<div class='dlgButtons'>
+				<div class='dlgSubButtons'><button type='button' id='note_move' class='ui-button ui-corner-all'><?php print __esc('Move', 'weathermap'); ?></button><button type='button' id='note_clone' class='ui-button ui-corner-all' style='margin-right:24px'><?php print __esc('Clone', 'weathermap'); ?></button>
+				<button type='button' class='wm_submit ui-button ui-corner-all' style='font-weight:bold'><?php print __esc('Save', 'weathermap'); ?></button>
+				<button type='button' class='wm_cancel ui-button ui-corner-all'><?php print __esc('Cancel', 'weathermap'); ?></button>
+				</div>
+			</div>
+		</div>
+
 		<!-- Node Properties -->
 		<div id='dlgNodeProperties' class='dlgProperties' title='<?php print __('Node Properties', 'weathermap'); ?>'>
 			<div class='cactiTable'>
diff --git a/weathermap-cacti-plugin-mgmt.php b/weathermap-cacti-plugin-mgmt.php
index 57d481a..de1d505 100644
--- a/weathermap-cacti-plugin-mgmt.php
+++ b/weathermap-cacti-plugin-mgmt.php
@@ -1753,38 +1753,48 @@ function add_config($file) {
 		print '<h3>' . __('Path mismatch', 'weathermap') . '</h3>';
 	} else {
 		require_once __DIR__ . '/lib/editor.config-delete.php';
-		$file = basename($file);
-		$realfile = $weathermap_confdir . '/' . $file;
-		$lock = wm_config_lock($realfile);
-		if ($lock === false) {
+		require_once __DIR__ . '/lib/WeatherMap.config.php';
+		$directory_lock = \WeathermapConfig\acquire($weathermap_confdir, false);
+		if (!$directory_lock && (is_writable($weathermap_confdir) || file_exists($weathermap_confdir . '/.weathermap-config.lock'))) {
 			raise_message('path_missing', __esc('The configuration file is unavailable. Please retry.', 'weathermap'), MESSAGE_LEVEL_ERROR);
 			return;
 		}
 		try {
-			$title    = wmap_get_title($realfile);
-
-			db_execute_prepared("INSERT INTO weathermap_maps
-				(configfile, titlecache, active, imagefile, htmlfile, filehash, config)
-				VALUES (?, ?, 'on', '', '', '', '')",
-				[$file, $title]);
-
-			$last_id = db_fetch_insert_id();
-			$myuid   = (isset($_SESSION['sess_user_id']) ? intval($_SESSION['sess_user_id']) : 1);
-
-			db_execute_prepared('INSERT INTO weathermap_auth
-				(mapid, userid)
-				VALUES (?, ?)',
-				[$last_id, $myuid]);
-
-			db_execute_prepared('UPDATE weathermap_maps
-				SET filehash = LEFT(MD5(CONCAT(id, configfile, rand())), 20)
-				WHERE id = ?',
-				[$last_id]);
-
-			map_resort();
+			$file = basename($file);
+			$realfile = $weathermap_confdir . '/' . $file;
+			$lock = wm_config_lock($realfile);
+			if ($lock === false) {
+				raise_message('path_missing', __esc('The configuration file is unavailable. Please retry.', 'weathermap'), MESSAGE_LEVEL_ERROR);
+				return;
+			}
+			try {
+				$title    = wmap_get_title($realfile);
+
+				db_execute_prepared("INSERT INTO weathermap_maps
+					(configfile, titlecache, active, imagefile, htmlfile, filehash, config)
+					VALUES (?, ?, 'on', '', '', '', '')",
+					[$file, $title]);
+
+				$last_id = db_fetch_insert_id();
+				$myuid   = (isset($_SESSION['sess_user_id']) ? intval($_SESSION['sess_user_id']) : 1);
+
+				db_execute_prepared('INSERT INTO weathermap_auth
+					(mapid, userid)
+					VALUES (?, ?)',
+					[$last_id, $myuid]);
+
+				db_execute_prepared('UPDATE weathermap_maps
+					SET filehash = LEFT(MD5(CONCAT(id, configfile, rand())), 20)
+					WHERE id = ?',
+					[$last_id]);
+
+				map_resort();
+			} finally {
+				flock($lock, LOCK_UN);
+				fclose($lock);
+			}
 		} finally {
-			flock($lock, LOCK_UN);
-			fclose($lock);
+			if ($directory_lock) \WeathermapConfig\release($directory_lock);
 		}
 	}
 }
@@ -1989,50 +1999,54 @@ function map_duplicate($id, $titlecache, $configfile = null) {
 		$save['duration']     = 0;
 		$save['last_runtime'] = 0;
 
-		$newid = sql_save($save, 'weathermap_maps');
+		$confdir = __DIR__ . '/configs';
 
-		if ($newid) {
-			db_execute_prepared("INSERT INTO weathermap_auth
+		$oldfile = $confdir . '/' . $map['configfile'];
+		$newfile = $confdir . '/' . $save['configfile'];
+
+		require_once __DIR__ . '/lib/WeatherMap.config.php';
+		$lock = \WeathermapConfig\acquire($confdir);
+		if (!$lock) {
+			raise_message('map_message', __('Could not lock map configurations.', 'weathermap'), MESSAGE_LEVEL_ERROR);
+			return;
+		}
+		$newid = 0;
+		$created = false;
+		try {
+			$contents = is_file($oldfile) ? file_get_contents($oldfile) : false;
+			if ($contents === false) throw new RuntimeException(__('The new Map with the name %s was unable to locate the config file %s to copy', $save['titlecache'], $map['configfile'], 'weathermap'));
+			$contents = str_replace("TITLE {$map['titlecache']}", "TITLE {$save['titlecache']}", $contents);
+			if (!\WeathermapConfig\atomicWrite($newfile, $contents, false, null, true, $lock)) throw new RuntimeException(__('Could not save the map configuration.', 'weathermap'));
+			$created = true;
+			$newid = sql_save($save, 'weathermap_maps');
+			if (!$newid) throw new RuntimeException(__('Could not register the new map.', 'weathermap'));
+
+			if (db_execute_prepared("INSERT INTO weathermap_auth
 				(userid, mapid)
-				SELECT userid, '$newid' AS mapid
+				SELECT userid, ? AS mapid
 				FROM weathermap_auth
-				WHERE mapid = ?",
-				[$id]);
-
-			db_execute_prepared("INSERT INTO weathermap_settings
+				WHERE mapid = ?", [$newid, $id]) === false) throw new RuntimeException(__('Could not register the new map.', 'weathermap'));
+			if (db_execute_prepared("INSERT INTO weathermap_settings
 				(mapid, groupid, optname, optvalue)
-				SELECT '$newid' AS mapid, groupid, optname, optvalue
+				SELECT ? AS mapid, groupid, optname, optvalue
 				FROM weathermap_settings
-				WHERE mapid = ?",
-				[$id]);
-
-			raise_message('new_map_' . $newid, __('The new Map with the name %s was created using config file %s', $save['titlecache'], $save['configfile'], 'weathermap'), MESSAGE_LEVEL_INFO);
-
-			$confdir = __DIR__ . '/configs';
-
-			$oldfile = $confdir . '/' . $map['configfile'];
-			$newfile = $confdir . '/' . $save['configfile'];
-
-			if (file_exists($oldfile)) {
-				if (copy($oldfile, $newfile)) {
-					$contents = file_get_contents($newfile);
-
-					if ($contents !== false) {
-						$contents = str_replace("TITLE {$map['titlecache']}", "TITLE {$save['titlecache']}", $contents);
-
-						file_put_contents($newfile, $contents);
-					} else {
-						raise_message('title_fail_' . $newid, __('The new Map %s was copied, but its title could not be updated in the config file %s', $save['titlecache'], $save['configfile'], 'weathermap'), MESSAGE_LEVEL_WARN);
-					}
-				} else {
-					raise_message('copy_fail_' . $newid, __('The new Map with the name %s was unable to create the config file %s', $save['titlecache'], $save['configfile'], 'weathermap'), MESSAGE_LEVEL_ERROR);
+				WHERE mapid = ?", [$newid, $id]) === false) throw new RuntimeException(__('Could not register the new map.', 'weathermap'));
+		} catch (Throwable $error) {
+			// Only this attempt's records and successfully reserved file may be removed.
+			try {
+				if ($newid) {
+					db_execute_prepared('DELETE FROM weathermap_auth WHERE mapid = ?', [$newid]);
+					db_execute_prepared('DELETE FROM weathermap_settings WHERE mapid = ?', [$newid]);
+					db_execute_prepared('DELETE FROM weathermap_maps WHERE id = ?', [$newid]);
 				}
-			} else {
-				raise_message('missing_fail_' . $newid, __('The new Map with the name %s was unable to locate the config file %s to copy', $save['titlecache'], $map['configfile'], 'weathermap'), MESSAGE_LEVEL_ERROR);
-			}
-
-			weathermap_run_maps(__DIR__, true, [$newid]);
+			} finally { if ($created) unlink($newfile); }
+			raise_message('map_message', $error->getMessage(), MESSAGE_LEVEL_ERROR);
+			return;
+		} finally {
+			\WeathermapConfig\release($lock);
 		}
+		raise_message('new_map_' . $newid, __('The new Map with the name %s was created using config file %s', $save['titlecache'], $save['configfile'], 'weathermap'), MESSAGE_LEVEL_INFO);
+		weathermap_run_maps(__DIR__, true, [$newid]);
 	}
 }
 
@@ -3430,11 +3444,17 @@ function newMap($mapfile, $sourcemapfile = '', $title = '') {
 		if ($mapfile != '') {
 			if ($sourcemapfile != '') {
 				if (file_exists($sourcemapfile) && is_readable($sourcemapfile)) {
-					$map->ReadConfig($sourcemapfile);
+					if (!$map->ReadConfig($sourcemapfile) || !is_string($map->config_revision)) {
+						raise_message('map_message', __('The Source Map File name is not readable or does not exist!', 'weathermap'), MESSAGE_LEVEL_ERROR);
+						return;
+					}
 					if ($title !== '') {
 						$map->title = $title;
 					}
-					$map->WriteConfig($mapfile);
+					if (!$map->WriteConfig($mapfile, true)) {
+						raise_message('map_message', __('Could not save the map configuration.', 'weathermap'), MESSAGE_LEVEL_ERROR);
+						return;
+					}
 					raise_message('map_message', __('New Map file %s created from %s', basename($mapfile), basename($sourcemapfile), 'weathermap'), MESSAGE_LEVEL_INFO);
 				} else {
 					raise_message('map_message', __('The Source Map File name is not readable or does not exist!', 'weathermap'), MESSAGE_LEVEL_ERROR);
@@ -3443,7 +3463,10 @@ function newMap($mapfile, $sourcemapfile = '', $title = '') {
 				if ($title !== '') {
 					$map->title = $title;
 				}
-				$map->WriteConfig($mapfile);
+				if (!$map->WriteConfig($mapfile, true)) {
+					raise_message('map_message', __('Could not save the map configuration.', 'weathermap'), MESSAGE_LEVEL_ERROR);
+					return;
+				}
 				raise_message('map_message', __('New Map file %s created.', basename($mapfile), 'weathermap'), MESSAGE_LEVEL_INFO);
 			}
 		} else {
diff --git a/weathermap-cacti-plugin.php b/weathermap-cacti-plugin.php
index e905e0e..a6ec573 100644
--- a/weathermap-cacti-plugin.php
+++ b/weathermap-cacti-plugin.php
@@ -203,7 +203,7 @@
 
 					print '';
 
-					print "<img src='?action=liveviewimage&id=$id' />\n";
+					print wm_liveview_image_html($map, $id);
 					print $map->imap->subHTML('LEGEND:');
 					print $map->imap->subHTML('TIMESTAMP');
 					print $map->imap->subHTML('NODE:');