High CPU in second VS Code project window when Codex panel is opened, while first project window is already open

What version of the IDE extension are you using?

26.5417.40842 (latest prerelease)

What subscription do you have?

Plus

Which IDE are you using?

VS Code

What platform is your computer?

macOS on Mac mini (M4) (Darwin 25.4.0 arm64 arm)

What issue are you seeing?

When I open Codex in a second VS Code window that already has a workspace/project open, CPU usage spikes sharply in Code Helper (Renderer).

The first VS Code window also already has a project/workspace open, but it does not show the same high CPU behavior by itself. The spike happens when Codex is opened in the second project window.

This does not require any active chat. The issue happens even when the Codex panel is simply opened and left idle.

From VS Code's Help → Open Process Explorer, the highest consumer is the second project window (window[index]).

Observed behavior so far:

• First window already has a workspace/project open, and Codex can be open there with normal / low CPU
• Opening a second empty window: normal / low CPU
• Opening Codex in the second empty window: normal / low CPU
• Closing Codex in the second window, then opening a project/workspace there: normal / low CPU
• Opening Codex in that second project window: CPU becomes high
• This also reproduces with a very small / nearly empty folder, so it does not seem tied to one large project
• It also reproduces with no chat messages at all

What steps can reproduce the bug?

1. Open VS Code window [# 1]
2. Open any workspace/project folder in window [# 1]
3. Open the Codex panel in window #1
4. Confirm CPU usage is normal
5. Open VS Code window [# 2]
6. Do not open a project yet; optionally open the Codex panel and confirm CPU is still normal
7. In window [# 2], open any workspace/project folder (this also reproduces with a very small folder)
8. Open the Codex panel in window [# 2]

What is the expected behavior?

Opening the Codex panel in a second VS Code window with a workspace open should not cause sustained high CPU usage in Code Helper (Renderer) / window[index], especially while idle and without any chat activity.

Additional information

_No response_