Dismissing a clarification dialog and sending a follow-up message unexpectedly exits Plan mode

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

Version 26.908.40834

What subscription do you have?

Pro 20x

What platform is your computer?

No response

What issue are you seeing?

In this session, the conversation switched to Default mode after dismissing a qustion box and send a message, even though I had not explicitly switched modes.
The agent received an updated mode instruction and proceeded with implementation: it modified and committed code and generated local artifacts while I still believed we were discussing the plan.

What steps can reproduce the bug?

1. Start a conversation in Plan mode in the Codex desktop app.
2. Wait for Codex to display a multiple-choice clarification dialog.
3. Close the dialog using the × button without submitting an answer.
4. Send a regular follow-up message to continue discussing the plan.

What is the expected behavior?

The conversation should remain in Plan mode. Dismissing a clarification dialog or sending a follow-up message should not change the mode or authorize implementation.

Additional information

Impact
An ordinary clarification interaction unexpectedly enables execution, causing workspace changes before the user intends to leave Plan mode.

Reproduce the flow in the Codex desktop app: start in Plan mode, dismiss the multiple-choice clarification dialog with ×, then send a follow-up message. Trace how dialog dismissal and the follow-up update mode state; done means the conversation stays in Plan mode and does not begin implementation or create workspace changes.