Codex Desktop sidebar rendering corrupts on Linux Mint/X11 after scroll/hover unless GPU compositing is disabled

What version of the Codex App are you using (From "About Codex" dialog)?

Codex Desktop 2026.06.14.124606+fcc4da9a
Codex CLI 0.139.0

Version source: local Linux package/version diagnostics (dpkg-query -W codex-desktop), because I cannot copy the About dialog text from this environment.

Packaging note: this repro is from a community-built Linux package. The local dpkg-query -s codex-desktop description says: Community-built Linux package for Codex Desktop generated from the macOS DMG. The installed launcher also contains Linux compatibility wrapper code. I am filing here because the visible failure is in the Codex Desktop UI/sidebar repaint path, but the Linux packaging layer may be relevant.

What subscription do you have?

Unknown / not visible in local diagnostics.

What platform is your computer?

Linux 6.17.0-35-generic x86_64 x86_64

Additional local environment:

• OS: Linux Mint 22.3
• Desktop: Cinnamon 6.6.7
• Session: X11 (XDG_SESSION_TYPE=x11, XDG_CURRENT_DESKTOP=X-Cinnamon)
• GPU: AMD Radeon RX 6800 XT / Navi 21
• Mesa/renderer: AMD Radeon RX 6800 XT (radeonsi, navi21, LLVM 20.1.2, DRM 3.64, 6.17.0-35-generic), Mesa 25.2.8

What issue are you seeing?

The Codex Desktop left sidebar initially renders normally, but after scrolling the sidebar and hovering sidebar entries, the sidebar repaint becomes visually corrupted. The corruption appears as white/noisy artifacts over the left sidebar area while the rest of the app remains usable.

I reproduced this with the packaged launcher behavior before applying a local workaround. The issue is specifically triggered by sidebar repaint activity such as scroll and hover; a clean initial render alone is not enough to catch it.

What steps can reproduce the bug?

1. Start Codex Desktop on Linux Mint / Cinnamon / X11 without disabling GPU compositing.
2. Move the mouse over the left sidebar.
3. Scroll the sidebar up/down.
4. Hover over sidebar entries after scrolling.
5. Observe that the left sidebar becomes visually corrupted with white/noisy artifacts.

The same interaction sequence stays clean when starting Codex Desktop with GPU compositing disabled:

CODEX_ELECTRON_DISABLE_GPU_COMPOSITING=1 /usr/bin/codex-desktop

The resulting Electron command line includes:

--disable-gpu-compositing

Important: full GPU disable is not a viable workaround on this system. Starting with --disable-gpu did not produce a normal usable window and logged:

Error: GPU access not allowed. Reason: GPU access is disabled through commandline switch --disable-gpu and --disable-software-rasterizer.

What is the expected behavior?

The sidebar should repaint cleanly after scrolling and hovering, without visual corruption, using the normal launcher defaults.

Additional information

A local workaround is effective and narrowly scoped:

CODEX_ELECTRON_DISABLE_GPU_COMPOSITING=1 /usr/bin/codex-desktop

This keeps the app usable and avoids the sidebar corruption, whereas full --disable-gpu is too aggressive on this system.

I searched for existing issues with the concrete terms sidebar, Linux/X11, and disable-gpu-compositing before filing and did not find a direct duplicate. This looks like an Electron/Chromium GPU compositing repaint issue on Linux/X11 affecting the Codex Desktop sidebar rather than an updater/install-state issue.