macOS app scrolling is erratic, jumps, and resets position in long threads #17418

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

26.409.20454 (1462)

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Darwin 25.4.0 arm64 arm

What issue are you seeing?

Scrolling in the Codex macOS app is severely unstable and erratic...
When I scroll up or down, the view jumps unexpectedly, bounces, and sometimes resets to a different position. In longer threads, the app can suddenly jump away from the current reading position, which makes the app very hard to use.

This only happens in the Codex macOS app. Scrolling behaves normally in other apps on the same Mac.

Environment:

• Codex app: 26.409.20454 (1462)
• CLI: codex-cli 0.119.0
• Bundled: codex-cli 0.119.0-alpha.28
• Hardware: Apple Silicon (Mac mini M4 Pro, 64 GB RAM)
• macOS: 26.4.1

The issue was also present on macOS 26.4, so it does not seem specific to 26.4.1.

What steps can reproduce the bug?

1. Open the Codex macOS app.
2. Open an existing longer conversation/thread.
3. Scroll up and down using the mouse.
4. After a short time, scrolling becomes unstable: the view jumps, bounces, or resets to another position.

This happens repeatedly and is easy to reproduce in longer conversations.

Session ID: N/A
Token limit usage: N/A
Context window usage: N/A

This appears to be a UI scrolling issue rather than a model/session-specific issue.

What is the expected behavior?

Scrolling should be smooth and stable, with the view staying at the current position unless I intentionally continue scrolling.

Additional information

This has been happening for several days.
It is not limited to macOS 26.4.1; I also saw the same issue on macOS 26.4.
The problem appears to be specific to the Codex macOS app. Other apps on the same machine scroll normally...