[Windows][VS Code extension] System-wide UI stutter accumulates across sessions and clears only after sign-out

What version of the Codex extension are you using?

• VS Code extension identifier: openai.chatgpt
• Extension version: 26.810.52044
• Auto-update enabled; this was the current installed version during reproduction

What platform is your computer?

• Windows display version 25H2, build 26200.9168
• NVIDIA GeForce RTX 3070
• NVIDIA driver 32.0.16.1088
• Multiple monitors connected directly to the RTX 3070

What issue are you seeing?

After running several Codex coding-agent sessions through the VS Code extension for a few hours, the entire Windows interface becomes progressively laggy:

• dragging windows becomes choppy
• video playback renders poorly
• the degradation increases with additional agent sessions
• the lag remains after all agents finish
• the lag remains after every VS Code/Codex process is closed
• signing out of Windows and signing back in immediately restores smooth performance

This looks like a per-user-session graphical/resource retention problem triggered during sustained Codex extension use.

Steps to reproduce

1. Start from a fresh Windows sign-in with normal, smooth desktop performance.
2. Open VS Code with Codex extension openai.chatgpt version 26.810.52044.
3. Run several coding-agent sessions over multiple hours.
4. Finish all active agents.
5. Observe progressively degraded system-wide window dragging and video rendering.
6. Close every VS Code window and terminate remaining Code.exe, codex.exe, codex-code-mode-host.exe, and associated helper processes.
7. Observe that system-wide lag persists.
8. Press Win+Ctrl+Shift+B to reset the graphics driver.
9. Observe no improvement.
10. Sign out of Windows and sign back in.
11. Observe that performance immediately returns to normal.

Resource measurements

During the affected session:

• one long-lived codex.exe: approximately 809 MB RAM, 14,380 handles, 74 threads
• approximately 15,000–16,000 handles across Codex processes
• 22–25 node_repl helper processes were present, some several days old
• Desktop Window Manager: approximately 304 MB RAM, 2,741 handles, 164 threads

After signing out and signing back in:

• fresh Codex process: approximately 480 handles
• Desktop Window Manager: approximately 115 MB RAM, 1,880 handles, 117 threads
• desktop responsiveness was restored

Recent Windows event-log inspection found no nvlddmkm/display-driver timeout and no DWM application crash.

Expected behavior

Repeated Codex sessions should not progressively degrade system-wide graphics responsiveness. Codex and its helpers should keep resource usage bounded and release owned resources after tasks finish.

Recovery behavior / suspected scope

Closing all VS Code and Codex processes did not reverse the degradation, and resetting the graphics driver did not help. Signing out did help. This suggests resources or graphics state may remain retained by DWM or another per-user-session Windows component after the originating processes exit.

This does not establish the internal cause, but it makes permanent GPU degradation unlikely and points toward session-scoped resource retention.

Related issues

• #38750 reports similar system-wide stutter, but for Codex Desktop and recovery occurs immediately after exiting the app.
• #38745 reports severe Windows system/mouse stutter after launching Codex Desktop.

This report differs because the observed buildup followed sustained VS Code extension usage and persisted after VS Code/Codex exit; Windows sign-out was required to recover.

Start by reproducing the issue on Windows 25H2 with the VS Code extension and several agent sessions, then compare Codex, helper-process, and Desktop Window Manager resource counts before and after the lag. Done means identifying the retained session-scoped resource and demonstrating that repeated sessions no longer cause system-wide stutter after the processes exit.