[FEATURE] Desktop (Linux): setting to stop a bare Alt key press from opening the application menu

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

In the Claude Desktop app on Linux, tapping Alt on its own (press and release with no other key) pops up the application menu (File, Edit, …) and moves keyboard focus into it.

I use Left/Right Alt to turn my input method on and off (fcitx5, Japanese input). The IME handles the key, but the app still receives the Alt keyDown/keyUp, so the menu opens every time I switch input modes and my next keystrokes go to the menu instead of the prompt.

As far as I can tell there is no user-facing setting for this. The tap detection runs in the main process (before-input-event) and is gated only by a remote feature flag.

Proposed Solution

Add a setting to disable opening the application menu on a bare Alt press, similar to VS Code's window.customMenuBarAltFocus: false. F10 and the Alt+letter menu accelerators could keep working.

Alternative Solutions

• Changing the IME toggle keys, but that affects every other application.
• Patching app.asar, which isn't a reasonable option since the app enables the embedded asar integrity fuse.

Priority

Medium - Would be very helpful

Feature Category

Configuration and settings

Use Case Example

1. Type in the prompt with the IME off.
2. Press Right Alt (or Left Alt) to turn Japanese input on.
3. Expected: keep typing into the prompt. Actual: the application menu opens and takes focus.

Additional Context

• Claude Desktop 2.7032.0 (Linux beta, x86_64)
• NixOS, COSMIC desktop (Wayland, launched with --ozone-platform-hint=auto)
• fcitx5 with Mozc, Alt_L / Alt_R bound to deactivate / activate the input method