diff --git a/tiling-assistant@leleat-on-github/src/extension/moveHandler.js b/tiling-assistant@leleat-on-github/src/extension/moveHandler.js
index 7b0c524..d49f5cb 100644
--- a/tiling-assistant@leleat-on-github/src/extension/moveHandler.js
+++ b/tiling-assistant@leleat-on-github/src/extension/moveHandler.js
@@ -257,7 +257,12 @@ export default class TilingMoveHandler {
 
     _onMoveFinished(window) {
         try {
-            window.assertExistence();
+            // Ignore the expected error when the window was destroyed during the grab.
+            try {
+                window.assertExistence();
+            } catch {
+                return;
+            }
 
             if (this._tileRect) {
                 // Ctrl-drag to replace some windows in a tile group / create a new tile group
@@ -293,6 +298,12 @@ export default class TilingMoveHandler {
                 this._dragSprite = null;
             }
         } finally {
+            // Leaving it pending would re-enter _edgeTilingPreview() on a destroyed window
+            if (this._latestMonitorLockTimerId) {
+                GLib.Source.remove(this._latestMonitorLockTimerId);
+                this._latestMonitorLockTimerId = null;
+            }
+
             if (this._posChangedId) {
                 window.disconnect(this._posChangedId);
                 this._posChangedId = 0;
@@ -497,7 +508,8 @@ export default class TilingMoveHandler {
                     // Only update the monitorNr, if the latest timer timed out.
                     if (timerId === this._latestMonitorLockTimerId) {
                         this._monitorNr = global.display.get_current_monitor();
-                        if (global.display.is_grabbed())
+                        // check that the window still exists, and a grab is still active
+                        if (global.display.is_grabbed() && window.get_compositor_private())
                             this._edgeTilingPreview(window, grabOp);
                     }