Severe rendering artifacts in apply_patch diff view when features.tui2 is enabled

What version of Codex is running?

codex-cli 0.87.0

What subscription do you have?

plus

Which model were you using?

_No response_

What platform is your computer?

Linux

What terminal emulator and version are you using (if applicable)?

iterm2 3.6.6, tmux 3.5a

What issue are you seeing?

When features.tui2 is enabled, the apply_patch tool exhibits severe rendering corruption. The interface becomes chaotic, with text overlapping, ghost characters appearing, and misalignment of columns (as seen in the attached screenshot).

<img width="849" height="525" alt="Image" src="https://github.com/user-attachments/assets/ad59db11-74bd-42cb-9e14-057cecc89555" />

I have observed that this issue seems isolated to the diff rendering logic:

• Trigger: The issue only occurs during manual scrolling. If the TUI is allowed to auto-scroll or render statically without user interaction, the display is correct. The artifacts appear immediately when I try to scroll up or down through the diff.
• Scope: This is isolated to the diff rendering logic. Standard text output (including italics and bold) handles scrolling correctly without leaving residue.
• Frequency: The issue is intermittent but happens with a very high probability inside the diff view.

What steps can reproduce the bug?

1. Enable features.tui2.
2. Trigger the apply_patch tool (or any action that invokes the diff viewer).
3. Manually scroll through the output.
4. Observe the rendering of the diff output.

What is the expected behavior?

_No response_

Additional information

I am using tmux 3.5a, and this issue is not 100% reproducible but occurs with a very high probability specifically within the diff view.