[BUG] Main right-side vertical scrollbar hitbox doesn't reach the window edge in the Claude Code tab of the desktop app

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?

In the Claude Code tab of the Claude Desktop app on Windows (with the window maximized / full screen), the main right-side vertical scrollbar's clickable hitbox does not extend to the right edge of the window. Slamming the cursor to the far right (Fitts's law target) lands outside the scrollbar, so click-to-scroll fails.

This does not happen in the Claude Chat tab of the same app — the Chat tab's scrollbar is flush to the window edge and behaves correctly. The two tabs use different scrollbar/container rules.

What Should Happen?

The main vertical scrollbar's hitbox should extend all the way to the right edge of the window (matching the Claude Chat tab), so the cursor can be thrown to the screen edge for reliable click-to-scroll.

Error Messages/Logs

Steps to Reproduce

1. Open the Claude Desktop app on Windows 11 and maximize the window (full screen).
2. Switch to the Claude Code tab.
3. Open a conversation long enough to require scrolling.
4. Move the mouse cursor to the far right edge of the window, level with the scrollbar track.
5. Click — the click misses the scrollbar (cursor is outside the hitbox).
6. Repeat in the Claude Chat tab — the same gesture works correctly.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Desktop app v1.2773.0.0 (Windows MSIX). Bug is in the Claude Code tab embedded in the desktop app, not the CLI.

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_