[BUG] Claude for Mac UI broken in windowed mode (works in fullscreen)

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?

Claude for Mac has a UI rendering issue.

In windowed mode:

• text is clipped
• layout is misaligned
• parts of the UI appear broken or blank

In fullscreen mode:

• the issue disappears completely

The problem returns even after reinstalling the app.

Steps already tried:

• reinstalled the app
• restarted multiple times
• disabled GPU/hardware acceleration

Result:

• issue persists in windowed mode only

This looks like a rendering/scaling bug in Claude for Mac.

Issue occurs on the latest version (1.2581.0)

<img width="1792" height="1120" alt="Image" src="https://github.com/user-attachments/assets/45641b28-90a8-4f80-8d1a-cc9f8fb49b7f" />

<img width="1792" height="1120" alt="Image" src="https://github.com/user-attachments/assets/1db6736d-31a8-4dfb-a9cc-f7d91a8e8ff0" />

What Should Happen?

The Claude interface should render correctly in both windowed and fullscreen modes without clipping, layout issues, or broken UI elements.

Error Messages/Logs

No error messages. This is a UI rendering issue.

Steps to Reproduce

1. Open Claude Desktop app on macOS
2. Use the app in normal window mode (not fullscreen)
3. Observe UI rendering issues (cut text, black areas, broken layout)
4. Switch to fullscreen mode
5. Issue disappears in fullscreen

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

unknown

Claude Code Version

1.2581.0

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

<img width="1792" height="1120" alt="Image" src="https://github.com/user-attachments/assets/5f212543-32ec-422a-b84f-c6ca6a6dedc2" />

<img width="1792" height="1120" alt="Image" src="https://github.com/user-attachments/assets/3699f1fa-ac95-4e4d-81c7-e83eef0d2328" />