[BUG] Claude Code Extension open new editor window (won't stay in secondary side bar)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

In VS Code (Mac), t

<img width="1509" height="1028" alt="Image" src="https://github.com/user-attachments/assets/119cb328-737c-4f5d-934e-08530387b3b2" />

he Claude Code Extension opens as a code editor window for each new/existing chat. Much worse, opening another file from Explorer now opens a new code editor column.

What Should Happen?

chats should anchor into the secondary side bar

Error Messages/Logs

Steps to Reproduce

Open Claude Code Extension
Start new chat
Observe it starts in code editor window
Use Explorer to open some project file
Observe it starts a new code editor column

<img width="1509" height="1028" alt="Image" src="https://github.com/user-attachments/assets/318a5336-a4d1-4067-a8dc-24c0640be51c" />

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Code version 2.1.140.

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_