IDE Extension in GitHub codespace crashes the codespace

Was just facing this issue and then it was fixed. What I did:
Open the codespace
If the agent tab chosen is Codex, quickly switch to the default chat tab
Wait for some time
Switch to Codex
It'll hang for some time. I then opened a new tab in the browser to search for the issue and found this thread, when I went back to the codespace tab, found Codex has opened

I opened issue #28280, because I did not find this issue initially. I copy my bug report here to add some screenshots and the log output. The workaround of @eladdad did not work for me; the panel never recovered and started to show the login dialog.

What version of the IDE extension are you using?

26.5609.30741

What subscription do you have?

ChatGPT Plus

Which IDE are you using?

VS Code Insiders

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

When I open the Codex panel, the panel only shows an icon but does not load the content of the panel:

<img width="462" height="749" alt="Empty Codex panel" src="https://github.com/user-attachments/assets/a05f21e1-f87e-4fdd-a4a9-7bf6d2607cbe" />

After a while, the following message appears:
<img width="450" height="149" alt="Warning dialog with the title 'The window is not responding' and the description 'You can reopen or close the window or keep waiting'." src="https://github.com/user-attachments/assets/0aad383e-b542-488e-afda-1560a6f7b7ae" />

The output of the extensions gives the following log:

2026-06-15 10:23:09.306 [info] Activating Codex extension
2026-06-15 10:23:09.306 [info] [CodexMcpConnection] Spawning codex app-server
2026-06-15 10:23:09.306 [warning] [IpcClient] Received broadcast but no handler is configured method=client-status-changed
2026-06-15 10:23:09.724 [info] [CodexMcpConnection] Initialize received id=1
2026-06-15 10:23:09.911 [warning] [CodexMcpConnection] cli: message="codex_core_plugins::manager: failed to warm featured plugin ids cache error=remote featured plugin request to https://chatgpt.com/backend-api/plugins/featured failed with status 401 Unauthorized: {\"detail\":\"Unauthorized\"}"
2026-06-15 10:23:11.170 [warning] [CodexMcpConnection] cli: message="codex_core_plugins::manifest: ignoring interface.defaultPrompt[0]: prompt must be at most 128 characters path=C:\\Users\\LFernhomberg\\.codex\\.tmp\\plugins\\plugins\\ngs-analysis\\.codex-plugin/plugin.json"

What steps can reproduce the bug?

1. Open VS Code Insiders
2. Install Codex extension
3. Open Codex panel in chat area
4. Codex panel is empty and does not allow you to login

Based on the feedback of other bugs, I tried installing older versions as well as the release version. Furthermore, I renamed the ".codex" folder in the "Users" folder, so that it gets recreated. Both approaches did not fix the issue for me.

What is the expected behavior?

Codex panel loads correctly allowing me to login

Additional information

_No response_

I can confirm the same issue with code-server and the Codex IDE extension.

My environment:

• code-server running in a Docker container
• Codex extension version: openai.chatgpt-26.616.32156-linux-x64
• Extension path: /config/extensions/openai.chatgpt-26.616.32156-linux-x64
• Affected clients: desktop Chromium-based browsers
• Symptom: opening the Codex sidebar briefly works, then the whole code-server browser UI freezes

I applied the workaround described in this issue and it fixed the freeze.

The concrete fixes were:

1. Patch out/extension.js to avoid direct navigator checks in the Node extension host context.

The problematic checks looked like:

``js
typeof navigator<"u"
``

Replacing them with:

``js
false
``

prevented the PendingMigrationError: navigator is now a global in nodejs issue.

1. Patch the Codex webview preload behavior.

The generated webview entry file under:

``text
webview/assets/index-*.js
``

contained a very large Vite preload list using __vite__mapDeps([...]), which caused the Codex sidebar to eagerly preload hundreds of JS/CSS chunks when the sidebar iframe mounted.

Reducing that preload list so that only CSS chunks are preloaded fixed the freeze.

1. Remove static modulepreload links from:

``text
webview/index.html
``

After applying these changes and restarting the code-server container, the Codex sidebar loads normally in desktop Chromium browsers and the code-server UI no longer freezes.

So the root cause appears to be two separate compatibility issues:

• the extension accesses navigator in a Node extension host environment under code-server
• the Codex webview eagerly preloads too many Vite chunks, which overwhelms or breaks code-server’s webview resource loading path in desktop Chromium browsers

The second issue, the excessive webview preload list, seems to be the actual cause of the hard browser freeze in my setup.

A proper fix would probably be to make the Codex webview preload behavior more code-server-friendly, e.g. avoid eagerly preloading all JS chunks and only preload critical CSS/assets.

code --disable-gpu also works.