Canvas Drag Fix

Canvas Drag Fix

An Obsidian plugin that fixes Canvas drag-and-drop on Linux when an ordinary mouse is misclassified as a pen device by Chromium/Electron.

Symptoms this fixes

• Cards in Canvas can't be moved by click-and-drag
• Resizing Canvas cards from the sides doesn't work (corners may still work)
• Click-and-drag selection of canvas regions doesn't work
• Arrow connections can't be drawn from card handles
• Click, double-click, keyboard arrow movement, and corner-resize all still work

If only drag interactions are broken while clicks work fine, this is almost certainly the bug this plugin fixes.

Affected setups

• Linux guests in VMware Workstation/Fusion/Player
• Linux guests in VirtualBox
• ChromeOS Crostini Linux containers
• Some Wayland configurations
• Some bare-metal Linux setups with unusual XInput2 device topology

The bug is reproducible with or without sandboxing (firejail, snap, flatpak, AppImage). It's not specific to any sandbox or distribution.

How to verify the bug applies to you

Open Obsidian DevTools (Ctrl+Shift+I), go to the Console tab, type allow pasting and Enter, then paste:

(() => {
  const log = e => console.log(e.type, 'pointerType:', e.pointerType, 'button:', e.button);
  ['pointerdown','pointermove','pointerup'].forEach(t =>
    document.addEventListener(t, log, true));
  setTimeout(() => ['pointerdown','pointermove','pointerup'].forEach(t =>
    document.removeEventListener(t, log, true)), 10000);
})();

Try to drag a Canvas card. If the console logs pointerType: pen for an ordinary mouse, this plugin will fix it.

How it works

Obsidian's Canvas drag handler uses a strict equality check on the pointer type:

e.targetNode === this.wrapperEl && "mouse" === e.pointerType && 0 === e.button

Under the affected configurations, Chromium reports pointerType as "pen" even for a regular mouse, so the handler rejects the event and the drag never starts. This plugin registers capture-phase listeners on window for every relevant pointer event type. When a pen event fires, it rewrites pointerType to "mouse" in place using Object.defineProperty. Because we mutate the original event rather than dispatch a synthetic clone, the event's target, currentTarget, view, and propagation path stay correct. By the time Obsidian's downstream handlers see the event, it looks like a normal mouse event.

Caveats

• All pen events are rewritten as mouse events globally. If you have a real graphics tablet or stylus connected to this machine, disable the plugin first — it will mask pen pressure, tilt, and other stylus-specific data.
• The plugin only loads on desktop. It's a no-op on Obsidian Mobile, since the bug doesn't manifest there.
• This is a workaround, not an upstream fix. The underlying issue is in Chromium's XInput2 device classification. If/when Chromium fixes it or Obsidian relaxes the strict "mouse" check, this plugin becomes unnecessary.

Manual installation

1. Download main.js and manifest.json from the latest release.
2. Place them in your vault under <vault>/.obsidian/plugins/canvas-drag-fix/.
3. In Obsidian: Settings → Community plugins → reload installed plugins, then enable Canvas Drag Fix.

Building from source

npm install
npm run build

This produces main.js next to manifest.json. Copy both into your vault's plugin folder.

For development, use npm run dev which rebuilds on changes.

License

0BSD. See LICENSE in the repository root.