Enter key submits immediately in input on macOS, breaking Japanese IME conversion (kana to kanji)

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

260205.1301 (554)

What subscription do you have?

ChatGPT Plus

What issue are you seeing?

Enter key submits immediately in Plan-mode input on macOS, breaking Japanese IME conversion (kana→kanji)

Description

In the Codex macOS app, the input field used for asking questions in Plan mode (and/or providing alternative suggestions related to the Plan) submits immediately when pressing Enter.

This is problematic for Japanese users: with a Japanese IME on macOS, we press Enter to confirm conversion from hiragana to kanji. Because Enter triggers submission, the message is sent mid-sentence before the user intends to submit, which makes Plan-mode input very inconvenient. I (and Japanese users) will appreciate it if this behavior can be fixed.

What steps can reproduce the bug?

1. Open the Codex macOS app.
2. Switch to Plan mode.
3. Enable Japanese IME (macOS “Japanese – Romaji” / “Hiragana”, etc.).
4. Type a sentence in hiragana in the Plan-mode input field.
5. Press Enter to confirm kana→kanji conversion.
6. Observe that the message is submitted immediately.

What is the expected behavior?

• When the IME is composing/converting text, pressing Enter should confirm the conversion, not submit the message.
• The message should submit only when the user explicitly intends to submit (e.g., via a dedicated submit button, or a key combo like Cmd+Enter).

Additional information

Suggested Fix / Notes

• Detect IME composition state and prevent submission while composing (e.g., handle compositionstart / compositionend, event.isComposing, etc., depending on the input stack).
• Consider changing the submit shortcut to Cmd+Enter (or providing a setting), especially if the input is intended for multi-line planning text.