Text selection regression in Claude Code panel: click-to-extend selection no longer works

Description

Since a recent VS Code update, the standard double-click + click-to-extend text selection gesture no longer works in the Claude Code panel. The only mouse-based option is click-and-drag. The same gesture works correctly in other VS Code windows and other macOS applications.

Steps to Reproduce

1. Open the Claude Code panel in VS Code
2. Double-click a word to select it
3. Click somewhere further down to extend the selection to that point

Expected: Selection extends from the double-clicked word to the later click point (standard macOS multi-step selection behavior)

Actual: Selection is dropped; no extension occurs

Additional Findings

• Single-click → Shift+click also does not extend the selection
• Shift+arrow keys after double-clicking does work (current workaround)
• Behavior works correctly in other VS Code panels and all other macOS apps tested

Environment

• OS: macOS (Darwin 25.5.0, arm64)
• VS Code: 1.129.1
• Claude Code extension: v2.1.220