Excalidraw seems to update at a slower rate after entering Zen mode

[kpghostfox]

Description

Everything's in the issue title.
Changing power profiles didn't do anything. This performance regression makes it really hard to write by hand.

TriliumNext Version

0.102.1

What operating system are you using?

Other Linux

What is your setup?

Local + server sync

Operating System Version

Linux saturn 6.18.19 #1-NixOS SMP PREEMPT_DYNAMIC Thu Mar 19 15:08:51 UTC 2026 x86_64 GNU/Linux

Error logs

No response

[dosubot]

This looks related to an architectural gap in how the canvas widget handles layout changes. When Zen mode is toggled, it's a pure CSS class toggle (body.zen) that hides panels like #left-pane, .promoted-attributes-widget, etc. via display: none [1]. This silently changes the Excalidraw container's dimensions, but no resize or viewport refresh callback is sent to the Excalidraw component [2].

Specifically:

• Excalidraw is rendered with detectScroll={false} and zenModeEnabled={false} [3], so it doesn't auto-watch for container layout changes.
• The zenModeChanged event is fired [4], but only the close-zen button listens to it [5] — the canvas widget does not.
• There's no ResizeObserver in the canvas widget, unlike the Spreadsheet widget which has one explicitly [6].

This is the same class of bug as #6607, where collapsing promoted attributes (another container-dimension change) causes a ~1–2 cm mouse offset inside Excalidraw. Zen mode triggers a much larger layout shift, which would explain the degraded update rate — Excalidraw's internal rendering pipeline may be miscalculating its viewport bounds.

A likely fix would be adding a zenModeChanged listener to the canvas widget that calls Excalidraw's API to refresh or recalculate its viewport dimensions after the layout settles. As a workaround, you can try resizing the note pane slightly after entering Zen mode (e.g., drag any remaining border) — this forces Excalidraw to recalibrate, similar to the workaround described in #6447.

To reply, just mention @dosu.

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