Broken continuous horizontal text oscillation animation causes motion sickness

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

Version 26.519.41501 (3044)

What subscription do you have?

Pro

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

In the Codex desktop app, while model is working, text repeatedly animates horizontally. It jumps left, then moves right, then repeats continuously. The text does not settle, so I cannot read the conversation while the model is working without nausea or motion sickness. Please refer to the video below.

https://github.com/user-attachments/assets/e52d9571-0d27-40e5-acf1-f817a7c18c96

What steps can reproduce the bug?

Increase zoom level on 14-inch screen to about 150%.
Ask the Codex agent to write or edit code on disk. The issue happens most often when subagents are used, although it is not limited to subagent runs.

What is the expected behavior?

No jitter happens, no animation is played.

Additional information

The bug is reproducible only at high zoom levels. However, it still reproduces when macOS Reduce Motion is enabled.

If useful, I can open a separate issue for Codex not respecting the macOS Reduce Motion accessibility setting. Disabling most UI animation would help, since resizing the Codex window also causes motion sickness due to panes constantly moving around. Window resizing also occasionally produces visible screen tearing.