[BUG] Claude Desktop (Windows): steady ~1Hz full-screen flicker in dark mode only — single-GPU, HDR off

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Desktop exhibits a steady, periodic full-screen flicker at roughly 1 Hz (about once per second). The flicker is specific to dark theme — it occurs when the app is set to Dark, and when set to System while System resolves to dark. Switching the app to Light theme stops the flicker.

Key distinguishing characteristics:

• The flicker is periodic and continuous (~1/second), not triggered by mouse movement over the window, and not tied to hover, scroll, or any user interaction.
• It is theme-gated: present in Dark / (System→Dark), absent in Light.
• This is a single-GPU desktop with HDR disabled, so the known multi-GPU compositing trigger and the HDR black-screen issue do not apply here.

What Should Happen?

Confirmed Workaround

Launching the app with --disable-gpu-compositing completely eliminates the flicker.

Because the MSIX/Store build ignores ELECTRON_EXTRA_LAUNCH_ARGS and does not read an electron-flags.conf, the flag must be applied via a launcher that starts the packaged executable directly, e.g.:

$exe = Join-Path (Get-AppxPackage -Name "*Claude*").InstallLocation "Claude.exe"
Start-Process $exe -ArgumentList "--disable-gpu-compositing"

With the flag, the app uses CPU/software compositing and the flicker is gone, with no noticeable performance impact for a text-based UI. This points to the Electron GPU-compositing path (its interaction with Windows DWM) as the root cause, consistent with the other Windows compositing reports — but reproduced here on a single-GPU, HDR-off configuration, which the existing reports do not cover.

Error Messages/Logs

Steps to Reproduce

1. Install Claude Desktop (Microsoft Store / MSIX) on Windows 11.
2. Set the app theme to Dark (or System with the OS in dark mode).
3. Use the app normally with the window visible and GPU compositing active (i.e., launched without any flags).
4. Observe a steady full-screen flicker at ~1 Hz.
5. Switch the app to Light theme → flicker stops.
6. Relaunch with --disable-gpu-compositing → flicker does not occur in Dark theme.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Desktop version: 1.15200.0.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

This is for the Claude desktop app in Windows 11; no other terminal/shell used