Codex App: Markdown is not live-rendered when editing a sent prompt

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

26.818.41509 (build 6962)

What subscription do you have?

Not relevant

What platform is your computer?

Darwin 25.6.0 arm64

What issue are you seeing?

The new-prompt composer live-renders Markdown while typing. However, after a prompt has been sent and I choose to edit it, the edit composer shows the Markdown without the same live rendering.

This makes editing structured prompts harder and creates inconsistent behavior between composing a new prompt and editing a sent prompt.

What steps can reproduce the bug?

1. Open the Codex App.
2. Type a new prompt containing Markdown, such as a heading, bold text, a list, or a fenced code block.
3. Observe that Markdown is rendered live in the new-prompt composer.
4. Send the prompt.
5. Choose Edit on the sent prompt.
6. Observe that Markdown is no longer live-rendered in the edit composer.

What is the expected behavior?

Editing a sent prompt should use the same live Markdown rendering as the new-prompt composer.

Additional information

A related issue, #29168, discusses difficulty editing in the Markdown-styled prompt area, but it does not describe this specific inconsistency between the new-prompt composer and the sent-prompt editor.