[Windows][Desktop 26.810.7004.0] Typing and mouse stutter with repeated ResizeObserver loops

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

OpenAI.Codex 26.810.7004.0 x64 Microsoft Store package: OpenAI.Codex_26.810.7004.0_x64__2p2nqsd0c76g0

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64 Windows 11 Pro, version 25H2, build 26200 Graphics: - NVIDIA GeForce RTX 5070 - AMD Radeon integrated graphics

What issue are you seeing?

The ChatGPT/Codex Windows desktop application severely stutters while I type in a conversation. Typed characters appear with a noticeable delay, and the mouse pointer freezes or stutters at the same time.

The problem is isolated to the ChatGPT/Codex desktop application. Other Windows applications and demanding games run normally.

The stuttering correlates with repeated errors in the desktop renderer log:

[electron-message-handler] [desktop-notifications][global-error] ResizeObserver loop completed with undelivered notifications. rendererWebContentsId=1 rendererWindowAppearance=primary rendererWindowFocused=true rendererWindowId=1 rendererWindowVisible=true

There were 665 occurrences of this error across August 17–18, 2026.

During one directly observed reproduction on August 18, between approximately 06:28:56 and 06:29:06 PKT, dozens of these errors were recorded while I was typing. Several occurred only milliseconds apart.

During diagnosis:

• The application was using approximately 1.55 GB of working-set memory.
• The main application process, primary renderer, and GPU process were simultaneously active.
• Windows recorded no NVIDIA or AMD display-driver resets.
• Windows recorded no corresponding system-wide display failure.
• The issue also occurs while response text and reasoning/status content are streamed into the conversation.
• The keyboard and mouse work normally outside the desktop application.

Because keystrokes are delayed before submission, network or model response latency does not explain the problem.

The evidence suggests that the primary renderer is entering a layout/repaint feedback loop in the conversation view or message composer.

What steps can reproduce the bug?

1. Launch ChatGPT/Codex Desktop 26.810.7004.0 on Windows 11 x64.
2. Open an existing Chat or Codex conversation.
3. Click inside the message composer.
4. Begin typing a normal or moderately long message.
5. Continue typing while the text wraps or the composer changes height.
6. Observe that characters begin appearing late.
7. Move the mouse while continuing to type.
8. Observe that the pointer also freezes or stutters.
9. Submit the message or allow a response and reasoning/status content to stream.
10. Observe additional UI and pointer stuttering.
11. Inspect the desktop application log.
12. Observe bursts of:

ResizeObserver loop completed with undelivered notifications.

The issue is reproducible inside the desktop application but does not reproduce in other Windows applications or games.

Affected session ID:
01a01272-e0ee-7ec2-98b8-3ed4b856030b

Token-limit usage and context-window usage were not exposed by the desktop diagnostics.

What is the expected behavior?

Typing in the message composer should remain immediate and responsive. Every character should appear without delay, and mouse movement should remain smooth while typing or while responses and reasoning/status information are updating.

Changing the composer height, wrapping typed text, or adding streamed conversation content should not trigger repeated ResizeObserver loops or block the primary renderer.

The desktop application should remain responsive without requiring a restart, reinstall, cache reset, or GPU workaround.

Additional information

A closely related open report is:

#33996 — Windows Desktop: concurrent reasoning summaries correlate with ResizeObserver loops and UI freezes
https://github.com/openai/codex/issues/33996

My reproduction adds the following new information:

• The problem persists in the newer 26.810.7004.0 build.
• The stutter occurs during direct keyboard input in the message composer.
• Typed characters and mouse movement become delayed simultaneously.
• The ResizeObserver error burst was captured at the exact time the typing delay occurred.
• The problem occurs without a Windows display-driver reset or general system resource failure.

Another related report is:

#30428 — Windows app stutters when switching chats or opening Settings
https://github.com/openai/codex/issues/30428

I also previously reported a separate Windows desktop regression to OpenAI Support under Case 12706474. That issue concerned local Projects displaying “No projects” after a desktop update while Recent tasks remained visible. The issue persisted across subsequent desktop updates.

The previous affected versions included:

• 26.730.8199.0
• 26.803.5235.0

The current installed version is:

• 26.810.7004.0

I can provide sanitized desktop logs or a screen recording through an appropriate private channel. I am not publishing raw logs because they may contain local paths, project names, conversation identifiers, or other private information.