[Windows] PDF attachment preview panel closes immediately and download does nothing

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

Not captured.

What subscription do you have?

ChatGPT Plus.

What platform is your computer?

Codex desktop app on Windows. Exact Windows build and Codex app version were not captured.

What issue are you seeing?

PDF output attachments cannot be downloaded or previewed in the Codex desktop app.

The PDF attachment is visible in the conversation, including its filename and a download icon. However:

• Clicking the download icon does nothing: no download starts, no save dialog appears, and no error is shown.
• Clicking the PDF attachment to preview it opens the right-side panel for about one second, then the panel closes automatically.
• The PDF never remains open long enough to be viewed.
• The behavior is reproducible and prevents retrieving the generated PDF from the desktop app.

What steps can reproduce the bug?

1. Open the Codex desktop app on Windows.
2. Open a conversation containing a generated or attached PDF.
3. Click the download icon next to the PDF.
4. Observe that nothing happens.
5. Click the PDF filename/card to open the preview.
6. Observe that the right-side preview panel appears briefly and then closes by itself.

What is the expected behavior?

• Clicking the download icon should download the PDF or show a clear error.
• Clicking the PDF should open a persistent right-side preview panel with the PDF rendered inside it.
• If previewing or downloading fails, the app should display a useful error instead of silently closing the panel.

Additional information

The issue appears specific to the Codex desktop app surface. The failure affects both actions exposed for the same PDF: download and in-app preview.

Related but distinct reports:

• #37193 covers generated-file links that do nothing when clicked.
• #35441 covers Windows desktop preview failures for online Work output artifacts.

This report specifically covers PDF attachments where the preview panel flashes open and immediately closes, in addition to the download action doing nothing.

Start by reproducing the PDF attachment behavior in the Codex desktop app on Windows, checking both the download icon and the right-side preview panel. Trace the attachment actions from the desktop app entry point and identify why the panel closes and the download produces no response. Done means PDF downloads work or show a useful error, and preview remains open with the PDF rendered.