Nested docker layouts for REAPER — a native C++ extension that turns any REAPER window into a tile inside a multi-pane workspace. Up to 8 independent containers, drag-to-dock from outside, 32 saved workspaces, hotkeys for everything, Quick Switcher (Cmd+P-style), floating mode, and a launcher that remembers your layouts.
Capture any REAPER window — Media Explorer, FX Browser, Mixer, Actions, toolbars, or third-party ReaImGui scripts — into a tiling container with resizable splits, tabbed panes, and one-click workspace recall.
- Drag-to-dock — grab any REAPER window from outside MaxPane and drop it on a pane. Live preview shows the four split zones, the tab-bar zone, and the body-center forgiving zone. Shift+drop replaces the active tab.
- Up to 8 MaxPane containers in one REAPER session — independent
layouts, captured windows, and project state. Open via
MaxPane: Open Container,MaxPane: Open Container 2, … through 8. - Floating mode — detach the whole container into a top-level window with native chrome. Multi-monitor positions remembered. Always-on-top toggle for keyboard-monitor setups.
- Quick Switcher — bind one hotkey. Type a few characters. Fuzzy- match across every open tab (across every instance), every saved workspace, every favorite. Enter activates.
- 32 workspace slots + 32 favorite slots — bind hotkeys to any of them via REAPER's Actions dialog. Or use the single "Workspace pickup" action to reach all 32 from one binding.
- Persistent navigation bar at the top of every container. Home, Drag-to-dock, Quick Switch, Save workspace, Load▾, Settings, Support — actions that used to be buried in the right-click menu surfaced as a clean toolbar.
- Workspace launcher — when a container is empty, you see a card grid of saved workspaces with mini layout previews. One click loads. Right-click for Rename / Duplicate / Delete / Bind Hotkey.
- C-series UX wins — Reopen last closed tab (Cmd+Shift+T style), pinned tabs (sticky, sort to left, exempt from bulk close), tab Close-Others / Close-to-Right / Close-All, always-on-top floating.
- Settings dialog — auto-open, show nav bar, dark-mode override, default workspace, support links, all in one place.
- Toast bar + custom Save dialog — non-fatal feedback ("Workspace saved as 'Edit Mode'") via a 3-second toast strip; rename / duplicate collisions surface clearly instead of failing silently.
- Reliability — close-leak bugs that haunted v1.5.x are gone. The
close mechanism uses
WM_CLOSEas primary, action-toggle as fallback, startup ghost cleanup as safety net (see ARCHITECTURE.md for the full story).
Full per-bug detail in CHANGELOG.md.
- AU/VST/JSFX plugin window save & restore. Capture a floating
plugin UI into a MaxPane pane, save the workspace, restart REAPER —
the plugin reattaches to its pane on workspace load (with the
matching project open). Identity uses the same
(track GUID, FX GUID)pair REAPER itself stores in RPPFXID {…}blocks, so it survives FX slot reorder and plugin rename. Covers track FX, master FX, and take FX. - Inline hotkey binding. Right-click a workspace card → "Bind hotkey" now opens REAPER's keystroke-capture modal scoped to that specific slot — no more hunting through the full Actions dialog.
- Non-blocking update check on startup. REAPER startup no longer freezes for the HTTP round-trip; new "Automatically on REAPER startup" checkbox in Settings → UPDATES (default ON).
- Settings dialog compact redesign. ~26% shorter (380 → 280 px), tighter spacing, UPDATES section split out for clarity.
See CHANGELOG.md for the v2.0.4 section including known limitations (project-bound restore, plugin-side window scaling, etc.).
- Flexible split layouts — split panes horizontally or vertically to any depth (up to 16 panes). Drag splitter bars to resize on the fly. Double- click any splitter to reset to 50/50.
- Tabbed panes — multiple windows per pane with a tab bar. Drag tabs between panes, reorder within a pane. Each tab bar has a ▼ menu for pane operations.
- Solo / maximize — temporarily expand any pane to fill the entire container; full tree restored on exit.
- 5 layout presets — Two Columns, Left + Right Split, Three Columns, 2x2 Grid, Top + Bottom Split.
- Pinned tabs — sticky tabs sorted to the left of each pane, exempt from "Close Others" / "Close All".
- Tab colors — color-code tabs with 8 palette colors.
- 15 known REAPER windows — one-click capture for Mixer, Track Manager, Routing Matrix, Media Explorer, FX Browser, Project Bay, Region Manager, Region Render Matrix, Actions, Undo History, Navigator, Big Clock, Video, Performance Meter, Virtual MIDI Keyboard.
- Arbitrary window capture — grab any visible REAPER window (toolbars, third-party ReaImGui scripts like ReaBeat / ReaMD / reamix.me) via the "Open Windows" submenu, click-to-capture mode, or drag-to-dock.
- AU / VST / JSFX plugin UI capture (v2.0.4+) — capture a floating
plugin window via click-to-capture or drag-to-dock; identity is
saved as a
(track GUID, FX GUID)pair so it round-trips through workspace save/load and project reopen as long as the matching project is loaded. See Known limitations below for the project- bound and plugin-scaling caveats. - Favorites — pin frequently-used windows for instant access from any container's menu.
- 32 saved workspace slots — tree layout + captured windows snapshot. One click in the launcher or one hotkey binding to recall.
- Per-project state — layout is saved inside each
.RPPproject file via REAPER'sproject_config_extension_t, so different projects can have different MaxPane configurations and they load with the project. - Custom Save dialog — name input + clickable list of existing workspaces + dynamic status label so you know whether you're creating new or replacing.
- Up to 8 independent containers per session. Each instance has its own layout, captured windows, floating geometry, and per-project state. Workspaces and favorites are shared across instances.
- Quick Switcher — fuzzy-match across open tabs / workspaces / favorites. Bind your own hotkey.
MaxPane: Workspace pickup— single hotkey, prompt for slot number, load. One binding reaches all 32 slots.MaxPane: Reopen last closed tab— 16-entry per-container ring buffer; session-scoped.- Tab + pane keyboard nav — Next/Prev Tab, Next/Prev Pane, Solo Toggle, all bindable in REAPER's Actions dialog.
- Inline hotkey binding (v2.0.4+) — workspace launcher right-click → "Bind hotkey" opens REAPER's native shortcut-edit dialog scoped to that specific slot (no need to filter through the full action list).
- Accelerator hook — MaxPane action bindings fire even when MaxPane (or a captured pane) has focus — v1.x required REAPER's main window to have focus first.
- macOS arm64 + x86_64 — stable, fully functional.
- Windows x64 — stable as of v2.0.1 (closes #8 Windows mouse input).
- Linux x86_64 + aarch64 — stable as of v2.0.2 (#9 FX Browser close crash no longer reproduces on REAPER 7.69).
- Zero scripting / no dependencies — pure C++ extension using REAPER
SDK + WDL/SWELL. No
js_ReaScriptAPI, no ReaImGui, no Lua.
| Launcher hero | Settings dialog |
|---|---|
 |
 |
| Create grid layout | Assign windows to panes | Recall workspace |
|---|---|---|
 |
 |
 |
- In REAPER, go to Extensions → ReaPack → Import repositories…
- Paste this URL:
https://raw.githubusercontent.com/b451c/MaxPane/main/index.xml - Go to Extensions → ReaPack → Browse packages, search for MaxPane.
- Right-click → Install, then restart REAPER.
ReaPack will notify you of future updates automatically.
- Download the macOS binary from the Releases page
(
reaper_maxpane-arm64.dylibfor Apple Silicon,reaper_maxpane-x86_64.dylibfor Intel). - Copy it to
~/Library/Application Support/REAPER/UserPlugins/. - Restart REAPER.
- Open via Actions → MaxPane: Open Container, or assign a keyboard shortcut.
- Open MaxPane — run the action
MaxPane: Open Containerfrom REAPER's Actions menu. - First time? The launcher card grid is empty. Click any ▼ menu
button on a pane tab bar, or right-click any pane, to capture your
first window. Or click
[Drag]on the nav bar and drag a REAPER window from outside into the pane. - Split panes via the pane menu (Split Left/Right or Split Top/Bottom) or via drag-to-dock with an edge zone.
- Tabbed windows — drop multiple windows on the same pane; click tabs to switch, drag tabs between panes to rearrange.
- Save a workspace — click
[Save]on the nav bar (or right-click → Save Workspace…). Name it; it shows up in the launcher next time. - Recall a workspace — when a container is empty, click its card.
Or click
[Home]to overlay the picker on top of your current layout without disturbing it. - Bind a hotkey — in REAPER's Actions dialog, search for
MaxPane: Workspace Slot 1(etc.) orMaxPane: Workspace pickup(single hotkey for all 32 slots).
See CONTRIBUTING.md for the full workflow. Quick path:
git clone https://github.com/b451c/MaxPane.git
cd MaxPane
git clone https://github.com/justinfrankel/reaper-sdk.git cpp/sdk
git clone https://github.com/justinfrankel/WDL.git cpp/WDL
mkdir -p cpp/build && cd cpp/build
cmake .. -DCMAKE_BUILD_TYPE=Release
cmake --build . --parallelThen copy the resulting reaper_maxpane.{dylib,so,dll} to your REAPER
UserPlugins directory (paths above).
Architecture, module map, the three SetParent paths, the close-mechanism deep-dive, and the v2.0 feature surface — see ARCHITECTURE.md.
- REAPER 7.0+ (tested on 7.62, 7.68, 7.69, 7.73)
- macOS arm64 (Apple Silicon) and x86_64 (Intel) — stable
- Windows x64 — stable as of v2.0.1
- Linux x86_64 and aarch64 — stable as of v2.0.2 (validated on Ubuntu 24.04; FX Browser close crash from #9 no longer reproduces on REAPER 7.69 — covered by an upstream WDL/SWELL fix)
These are intentional design boundaries rather than bugs. The full detail is in CHANGELOG.md → 2.0.4 → Known limitations.
- Plugin restore needs the matching project open. Track GUIDs +
FX GUIDs are project-bound (REAPER itself stores them inside
.rppfiles). Workspace load reopens AU/VST UIs only when their owning tracks are present in a loaded project. Recommended workflow: open the project first, then load the workspace. For pure project- bound layouts, REAPER's RPP<MAXPANE_STATE>chunk auto-restores the layout on project reopen (save the.rppafter capture). - Container FX not supported in v2.0.4. Capturing the UI of an FX inside a REAPER 7.06+ container chain works at the time, but the identity isn't encoded in the workspace yet — re-add after restart. Top-level track FX and recFX (input FX) are fully supported.
- FX moved between tracks won't auto-restore. Strict track-GUID match; a toast surfaces "FX missing: …" so you know what skipped.
- Pre-v2.0.4 workspaces need a one-time re-capture for plugin
tabs. Legacy
arb:0:<plugin name>entries can't resolve to a live FX instance. Re-capture once, re-save. Non-FX tabs (Mixer, toolbars, scripts) restore as before. - Plugin window scaling is plugin-side. Most VST/AU GUIs render at a fixed resolution and don't dynamically resize to fit the MaxPane pane. The plugin sits at its native size — surrounded by whitespace if the pane is bigger, cropped to the pane viewport if smaller. MaxPane reparents the OS window but cannot force the plugin framework to redraw at a different scale. Resize the pane to roughly match the plugin's preferred size, or use the plugin's own zoom control if it exposes one. Same limitation in REAPER's native FX float windows.
Contributions welcome. Read CONTRIBUTING.md and ARCHITECTURE.md first. CI runs the full 5-platform matrix on every PR — your change has to be green there before review.
MaxPane is MIT-licensed and free. If it saves you time, please support its development:
MIT — Copyright (c) 2025–2026 b451c
- Forum thread — https://forum.cockos.com/showthread.php?t=307267
- REAPER — https://www.reaper.fm
- ReaPack — https://reapack.com
- REAPER SDK — https://github.com/justinfrankel/reaper-sdk
- WDL / SWELL — https://github.com/justinfrankel/WDL