[BUG] Claude Desktop header navigation buttons overlap at 100% Windows display scale (v1.6259.1)

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?

After updating to Claude Desktop v1.6259.1 on Windows, the navigation buttons in the top header bar (sidebar toggle, search, back/forward arrows) overlap each other and are difficult to click.

Environment:

• Claude Desktop version: 1.6259.1.0 (Windows Store / MSIX)
• - Windows display scale: 100% (1920x1200, DELL U2412M)
• - - OS: Windows 11

Steps to reproduce:

1. Install or update to Claude Desktop v1.6259.1
2. 2. Use Windows display scale set to 100%
3. 3. Open Claude Desktop — the header navigation buttons overlap

Workaround:
Pressing Ctrl+= inside Claude (zoom in) separates the buttons visually.

What Should Happen?

The header navigation buttons (sidebar toggle, search, back/forward) should be properly spaced and not overlap each other, as was the case in previous versions.

Error Messages/Logs

Steps to Reproduce

a1. Update Claude Desktop to v1.6259.1 on Windows

1. Ensure Windows display scale is set to 100%
2. 3. Open Claude Desktop
3. 4. Observe the top header bar — sidebar toggle, search, and back/forward arrow buttons are overlapping

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.6259.1 (Claude Desktop)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_