Windows desktop: Japanese IME becomes unresponsive in Chat and Codex until focus moves to another text field

Summary

In the new unified ChatGPT desktop app for Windows, Microsoft Japanese IME repeatedly becomes unresponsive in both the Chat and Codex surfaces.

Japanese input starts working again immediately after moving focus to another Windows text field (for example, the taskbar Search box) and then returning to the app. The problem later recurs.

Environment

• Windows, x64
• Unified ChatGPT desktop app (Chat / Work / Codex)
• AppX package: OpenAI.Codex
• Package version: 26.707.12708.0
• Packaged executable observed in Windows events: ChatGPT.exe
• Input method: Microsoft Japanese IME

Steps to reproduce

1. Launch the unified ChatGPT desktop app.
2. Open either Chat or Codex.
3. Start typing and converting Japanese text with Microsoft Japanese IME.
4. The IME/input composition eventually becomes unresponsive and Japanese text can no longer be entered normally.
5. Click another Windows text field, such as the taskbar Search box.
6. Japanese IME works in that field.
7. Return to ChatGPT/Codex; Japanese input works again temporarily.
8. The issue later repeats.

Expected behavior

Japanese IME composition should remain responsive while typing in both Chat and Codex.

Actual behavior

Japanese IME becomes unusable inside the app until keyboard focus is moved to another Windows text field. The issue occurs in both Chat and Codex, so it does not appear limited to one surface.

Troubleshooting already attempted

• Repaired the Windows app from Settings > Apps > Installed apps > Advanced options > Repair
• Restarted Windows
• Enabled Microsoft IME's compatibility option to use the previous IME version
• The problem still occurs

Windows event evidence

During local diagnostics over the preceding 24 hours:

• Windows Application log recorded 20 Application Error events (Event ID 1000) for the packaged app's ChatGPT.exe
• Exception code in all observed events: 0xc06d007f
• Faulting module: unknown
• No corresponding crash events were found for ctfmon.exe, TextInputHost.exe, Microsoft IME, or InputExperience

This does not by itself prove that the application errors cause the IME focus problem, but the timing and absence of an IME-side crash may be useful for investigation.

Impact

Japanese text input is repeatedly interrupted in both Chat and Codex. Focus-switching is only a temporary workaround; the desktop app is not reliably usable for Japanese input.