[BUG] Extension 2.1.228: Claude Code panel renders blank/gray across multiple VS Code windows

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?

Environment

• OS: Ubuntu 24.04.4 LTS
• VS Code: Snap package, latest/stable channel, rev 254
• Extension: anthropic.claude-code, auto-updated 2.1.226 → 2.1.228 on 2026-08-12 ~01:19 local time

Description

The Claude Code panel renders as a blank/gray area (no chat content) inside its webview, while the rest of the VS Code window (editor, sidebar, other panels) renders normally.

Steps to reproduce

1. Have anthropic.claude-code auto-update to 2.1.228.
2. Open the Claude Code panel in VS Code.
3. Panel shows blank/gray instead of the chat UI.

Additional details

• Never occurred before the auto-update to 2.1.228; not present on 2.1.226/2.1.227.
• Now reproducing across multiple simultaneously open VS Code windows (unrelated projects/workspaces), suggesting a shared extension-host or webview regression rather than something project-specific.
• Workaround: Developer: Reload Window temporarily fixes it, but it recurs.
• Attempted to downgrade to 2.1.227 via:

code --install-extension anthropic.claude-code@2.1.227

This installed successfully, but VS Code's extension auto-update silently reverted it back to 2.1.228 shortly after.

<img width="1759" height="668" alt="Image" src="https://github.com/user-attachments/assets/bb723ce0-c64d-4b1d-9a83-3d47ea0d07c5" />

What Should Happen?

What Should Happen?

The Claude Code panel should render its normal chat UI (conversation history, input box, etc.) after the extension updates — consistent with how it rendered on 2.1.226/2.1.227 — without requiring a manual "Reload Window" to recover, and without needing to fall back to an older extension version to get a working panel.

Error Messages/Logs

Steps to Reproduce

What Should Happen?

The Claude Code panel should render its normal chat UI (conversation history, input box, etc.) after the extension updates — consistent with how it rendered on 2.1.226/2.1.227 — without requiring a manual "Reload Window" to recover, and without needing to fall back to an older extension version to get a working panel.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.227

Claude Code Version

2.1.228 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_