macOS app: Cmd+Z in main composer undoes prior typing instead of undoing pasted text

[jaewun]

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

Codex 26.409.20454

What subscription do you have?

Pro

What platform is your computer?

Darwin 25.3.0 arm64 arm

What issue are you seeing?

macOS app: Cmd+Z in main composer undoes prior typing instead of undoing pasted text

In the Codex macOS app, the main message composer appears to handle undo history incorrectly after a paste.

What steps can reproduce the bug?

1. Open the main message composer in the Codex macOS app.
2. Type some text.
3. Paste additional text into the same composer.
4. Press Cmd+Z.

What is the expected behavior?

Cmd+Z should undo the most recent edit, which is the pasted text.

Instead of just removing the pasted text, Cmd+Z also undoes text that was typed before the paste.

Additional information

Scope / comparison

• Affected: main message composer
• Not affected: editing an already-sent message
• Because the edit box for already-sent messages behaves correctly, this looks specific to the main composer rather than a general macOS/app undo issue.