VS Code windows can get stuck with a black screen if 2 simultaneous "new chat response" messages occur

[sean-mcmanus]

Does this issue occur when all extensions are disabled?: ? (I don't think extensions can cause this issue)

Version: 1.133.0-insider (user setup)
Commit: 780ea33
Date: 2026-08-06T02:53:01Z
Electron: 42.8.0
ElectronBuildId: 14845705
Chromium: 148.0.7778.280
Node.js: 24.18.0
V8: 14.8.178.38-electron.0
@github/copilot: 1.0.78
@github/copilot-sdk: 1.0.9-preview.3
OS: 780ea33

Steps to Reproduce:

UPDATE: These repro steps are out-of-date: see the response below for the updated repro steps.

1. Open 30 VS Code instances with 30 worktrees of some large repo with 30 agents running (you can have Copilot write a script to generate the worktrees) with 128 GB of RAM. With WSL (in a Dev Box).

Bug: Randomly (as in it works initially and then randomly repros over time), a random instance gets a black screen that is unusable. How can I get more info diagnose the cause? It seems like some rendering bug. It just started happening today when I switched from 20 to 30 instances. I don't believe I'm running out of memory because my memory has room and I can get it to run out of memory by using a larger workspace and it gives me a different error (the out of memory popup).

I'm trying to see if Copilot can help diagnose the cause...it's setting up some stuff to try.

[deepak1556]

Very likely related to #261660 , see if minimize and restore brings the rendering.

Can you capture https://github.com/microsoft/vscode/wiki/Runtime-debugging#using-etw-on-windows with only CPU Usage and GPU activity, also switch logging mode to memory given the random nature of the issue. Send it to vscode-logs@microsoft.com , also record the process tree of the app and the pid of windows that exhibited the behavior.

[sean-mcmanus]

Robo (@deepak1556) I figured out the repro -- it happens when 2 near-simultaneous "New chat response" messages come in (from the accessibility.signals.chatUserActionRequired setting announcement == auto, see https://github.com/microsoft/vscode/blob/main/src/vs/workbench/contrib/chat/browser/accessibility/chatAccessibilityService.ts). Still sort of random, but I can repro it after several tries. The stuck black screen can happen to 1 or both windows (not to the other windows that don't receive the new chat response). The 30 VS Code instances I don't believe are necessary (I could confirm that later if necessary...it might also be possible to construct a small repro extension to make it even easier to repro). The repro and symptom do not sound like that linked issue. It stopped reproing for a few days because I was only sending chat messages to one VS Code window at a time (even with the 30 VS Code instances still).

I sent the OneDrive link to the ETL files and the other info in email.

[sean-mcmanus]

I reproed the bug with only 16 VS Code instances open -- this time, Copilot is busy doing something in the background, but I can't see what it's doing (I can tell, because the session in progress appears when I try to close the window). Also, Copilot created an extension that it said could potentially repro it more easily, but I haven't had time to try it yet.

[deepak1556]

Can you share the extension over the mail, I have a fix in the works based on the etw findings. If there is a reliable repro would help test it before I push it across in the runtime. Thanks!

[sean-mcmanus]

Robo (@deepak1556) With the extension I was able to repro it like ~10 times so far, but I'm still unable to find a way to get it to repro consistently. Did you still want the extension? Just the vsix and/or the source code? Do I send it to vscode-logs@microsoft.com? I've reproed it with as few as 2 VS Code instances open, but it seems easier to repro with at least 5, and opening VS Code instances at the same time a chat message arrives might increase the repro probability. When the bug repros with the extension, it seems to impact multiple instances at the same time like 2-4 of the 5 instances instead of the expected 1 instance were the bug to be randomly independent for each instance.

[deepak1556]

If you can share the extension source thats better and you can send it to vscode-logs@microsoft.com, thanks!