[BUG] "Secondary Sidebar not supported in this version of VSCode" warning on startup

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?

When launching Antigravity IDE or opening a chat, the following warning message appears:

"Secondary Sidebar not supported in this version of VSCode. Please update your VSCode to use. Opening in Activity Bar instead."

The Claude Code panel falls back to the Activity Bar instead of opening in the Secondary Sidebar as intended.

!Image

What Should Happen?

Sidebar suport.

Error Messages/Logs

Secondary Sidebar not supported in this version of VSCode. Please update your VSCode to use. Opening in Activity Bar instead.

Steps to Reproduce

1. Open Antigravity IDE
2. Warning message appears automatically on startup
3. Claude Code panel opens in Activity Bar instead of Secondary Sidebar

Claude Model

Other

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.15

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

• The warning tells users to "update VSCode" but users cannot update VSCode separately since it's bundled with Antigravity
• This is confusing UX since the user has no action they can take to resolve the warning
• Suggested fix: Either upgrade the bundled VSCode base to 1.64+ or suppress the warning when running inside Antigravity