[Windows][26.901.6511.0] Open Terminal and toggle bottom panel silently do nothing

Environment

• Microsoft Store package: OpenAI.Codex 26.901.6511.0 (verified locally).
• Windows build reported by the local runtime: 10.0.26200.0.
• Existing local folder-backed task, Windows filesystem; agent commands run successfully in PowerShell.
• Workspace is not a Git repository (git status reports that fact, not a dubious-ownership error).
• Configured integrated-terminal shell has not been verified.

Reproduction

1. Open the existing local task.
2. Choose View → Open Terminal (French UI: Affichage → Ouvrir le terminal).
3. Choose View → Toggle bottom panel (French UI: Afficher/masquer le panneau inférieur), or press Ctrl+J.

Neither action opens a visible panel. No actionable error is displayed. The side-panel tab picker offers Files, Side chat and Browser, but no terminal. Files open successfully in the side panel.

The user reports that restarting the application and subsequently restarting Windows did not resolve the problem. This has not been tested across other tasks.

Expected behavior

The bottom panel and integrated terminal should open, or display an actionable error explaining why the terminal cannot start.

Diagnostic observations

• The app tool open_in_codex with target terminal and placement bottom repeatedly returns status: queued, including after navigating explicitly to the active task.
• read_thread_terminal reports an empty cwd, shell unknown and no terminal output.
• At 2026-09-08 18:08:57 UTC and 18:09:30 UTC, desktop logs record the open_in_codex renderer handler starting and returning success. This confirms handler execution, not successful terminal creation.
• Around these attempts, the renderer logs ResizeObserver loop completed with undelivered notifications. There were 508 occurrences across the daily log files examined. Causality has not been established; this may be unrelated UI noise.
• Searches of those logs did not reveal terminal/PTY startup or startup-failure messages, apart from terminal-read tool calls. Process/module monitoring was not performed, so absence of log messages is not proof that no backend process ran.

Related reports

• https://github.com/openai/codex/issues/37104 — similar silent terminal/bottom-panel failure, reported for Windows/WSL; closed as completed on August 31. The current observation is in a Windows/PowerShell agent workspace on a newer app build. A common root cause is not confirmed.
• https://community.openai.com/t/codex-terminal-not-opening/1382344 — other users reporting failure to open the integrated terminal.

Could maintainers check whether the existing-task terminal target/panel routing problem still affects this Windows build, and recommend a supported diagnostic or recovery step?

This report was prepared with Codex assistance from user observations and local logs. Private task IDs, local user paths, screenshots and full logs are intentionally omitted.

Start with the renderer open_in_codex handler and the terminal target/panel routing, reproducing the issue on the reported Windows build with an existing local task. Check the related terminal-read diagnostics and renderer logs while testing the configured shell. Done means Open Terminal and Toggle bottom panel show the terminal, or present an actionable startup error.