[BUG] Extension Sidebar Icons Disappear When Claude Code Extension is Enabled in Antigravity IDE

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?

Custom extension sidebar icons (Activity Bar icons from viewsContainers.activitybar) disappear in Antigravity IDE when the Claude Code extension (anthropic.claude-code) is installed and enabled. Disabling Claude Code immediately restores all sidebar icons.

What Should Happen?

Environment

• IDE: Antigravity IDE (VS Code fork by Google)
• IDE Version: 1.104.0
• OS: Linux (also reported on other platforms)
• Claude Code Extension Version: 2.0.75

Expected Behavior

All extension sidebar icons should persist in the Activity Bar regardless of which other extensions are installed.

Actual Behavior

• Custom viewsContainers sidebar icons disappear after IDE restart
• The following warning appears in the extension's runtime status:

``
View container 'agTelemetryContainer' does not exist and all views registered to it will be added to 'Explorer'.
``

• Views are moved to the Explorer panel as a fallback, but the custom sidebar icon is gone

Workaround

Disabling the Claude Code extension immediately restores all custom sidebar icons for other extensions.

Additional Context

• This issue appears to affect multiple users and multiple extensions, not just one specific extension
• Related discussion: https://www.reddit.com/r/google_antigravity/comments/1poujdj/extension_icons_not_showing_in_sidebar/

Possible Causes

1. Claude Code may be registering view containers in a way that conflicts with or overrides other extensions' container registrations
2. There may be a race condition in how Antigravity IDE processes multiple extensions' viewsContainers contributions
3. Claude Code's large size (220+ MB) may be causing initialization timing issues

Impact

• Users cannot use Claude Code alongside other extensions that have custom sidebar icons
• This forces users to choose between AI assistance (Claude Code) and other productivity tools

Requested Fix

Please investigate the interaction between Claude Code's view container registration and other extensions' viewsContainers.activitybar contributions in Antigravity IDE.

Error Messages/Logs

Steps to Reproduce

1. Install Antigravity IDE
2. Install any extension that registers a custom viewsContainers in the activitybar (e.g., AG Telemetry, or any other extension with a custom sidebar icon)
3. Verify the extension's sidebar icon appears in the Activity Bar
4. Install the Claude Code extension (anthropic.claude-code)
5. Restart Antigravity IDE
6. Observe that the custom sidebar icons either:

• Appear briefly then disappear, OR
• Do not appear at all

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.76 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_