[BUG] v2.1.78 Windows: text selection in chat selects entire message block instead of partial selection

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?

Since upgrading to v2.1.78 on Windows, text selection in the Claude Code desktop chat interface is broken.

Behavior before v2.1.78: I could click and drag to select any portion of text in a chat message, then copy it normally with Ctrl+C.

Behavior in v2.1.78: When I try to select a portion of text inside a chat message, the entire message block gets selected instead of just the highlighted portion. This makes it impossible to copy a specific part of a response.

This regression appeared after the automatic update to v2.1.78 tonight. The previous version (v2.1.77) worked correctly.

What Should Happen?

Clicking and dragging over text should select only the highlighted portion, allowing the user to copy just that specific text with Ctrl+C — exactly as it worked in v2.1.77 and earlier.

Error Messages/Logs

Steps to Reproduce

1. Open Claude Code desktop app (v2.1.78) on Windows 10
2. Start a new chat and get any response from Claude
3. Try to click and drag to select a specific word or phrase within the response
4. Observe that the entire message block gets selected instead of just the dragged portion
5. Try Ctrl+C — it copies the entire message, not the intended selection

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.77

Claude Code Version

2.1.78

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

• Windows 10 Home 10.0.19045 (Italian locale)
• Using Claude Code desktop app (not CLI/web)
• The auto-updater updated from v2.1.77 to v2.1.78 without explicit user confirmation
• As a workaround, auto-updater has been disabled via "autoUpdaterStatus": "disabled" in settings.json