VS Code: opening a generated image preview freezes Codex chat on Linux

What version of the IDE extension are you using?

26.908.40401 (openai.chatgpt)

What subscription do you have?

Not provided.

Which IDE are you using?

Visual Studio Code 1.138.0

What platform is your computer?

Ubuntu 24.04.5 LTS

uname -mprs:

Linux 7.0.0-31-generic x86_64 x86_64

What issue are you seeing?

Opening a generated image preview freezes the Codex chat in VS Code. The rest of VS Code remains open. Reloading the VS Code window and opening the image again reproduces the freeze.

The image files decode correctly, and the affected chat continued working in the background. This appears to be a chat interface/preview problem, but the exact cause has not been established.

Codex logs repeatedly report:

ResizeObserver loop completed with undelivered notifications.

What steps can reproduce the bug?

1. Open a Codex chat containing a generated PNG image.
2. Open the image preview in that chat.
3. Observe that the Codex chat freezes while VS Code remains open.
4. Run Developer: Reload Window.
5. Reopen the chat and open the image again; the freeze recurs.

These reproduction steps are reported by the user. The diagnostic observations below were checked against local files and logs.

What is the expected behavior?

The generated image preview should open and close without freezing the chat. The chat should remain interactive and continue displaying updates.

Additional information

Observed on 2026-09-16. Times below are CEST (UTC+02:00).

• Affected thread ID: 01a0a95e-4985-7061-819d-236667a18bbe.
• Both generated PNG files pass full Pillow decoding and PNG integrity verification:
  • First collage: 1881 × 836, RGB, 1,878,379 bytes.
  • New individual-key draft: 1204 × 1306, RGBA, 952,693 bytes.
• Backend history records successful image generation at 11:12:20, followed by further assistant activity.
• The affected chat became active at 11:12:12.471. Representative entries from the extension's Codex.log:

  2026-09-16 11:12:12.700 [error] [desktop-notifications][global-error] ResizeObserver loop completed with undelivered notifications.
  2026-09-16 11:12:13.055 [error] [desktop-notifications][global-error] ResizeObserver loop completed with undelivered notifications.
  2026-09-16 11:12:20.310 [error] [desktop-notifications][global-error] ResizeObserver loop completed with undelivered notifications.
  2026-09-16 11:12:20.360 [error] [desktop-notifications][global-error] ResizeObserver loop completed with undelivered notifications.
  

• The preceding window reload at 11:09:09 ended the extension host normally with exit code 0.
• Inspected main/renderer/extension-host logs did not show a matching renderer-process crash, out-of-memory event, or image-decoding error.
• These layout errors correlate with the affected chat being displayed, but do not prove the cause. Other chats also log this error.

Suggested workaround: open the saved PNG in an external image viewer instead of using the Codex image preview. This is a workaround, not a confirmed fix.

Possibly related: #44145 (VS Code webview becomes unusable after opening reasoning details, same layout error) and #33782 (image-heavy desktop thread freezes with the same error). Their platforms or triggers differ; a shared root cause is unconfirmed.

No conversation transcript, generated images, credentials, or full logs are attached.

Reproduce the freeze by opening a generated PNG in the Codex chat, then inspect the extension's Codex.log for the repeated ResizeObserver errors. Compare the behavior with related issues #44145 and #33782, while checking that the image decodes and no renderer crash is reported. Done means the preview opens and closes without freezing the chat or stopping updates.