[BUG] Claude Desktop App: vertical wide stripe hiding part of the text

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?

Hi
It started to happen on 15.04. You can see the problem on the screenshot. Some vertical line, like frame of the window hides part of the text, I cannot close it. It is not visible only if I close left menu.

<img width="1324" height="912" alt="Image" src="https://github.com/user-attachments/assets/96220eaa-81f4-42cb-af30-8cf461139b0f" />

What Should Happen?

The vertical stripe should not be there at all - it is some broken frame.

Error Messages/Logs

Steps to Reproduce

1. I just open the desktop app on my mac -> new session in Claude Code
2. add some text, post, wait for reply
3. go to the left menu, you can resize it or just click -> this stripe appears. It is a problem in both dark and light modes.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.3109.0 (35cbf6) 2026-04-16T20:32:01.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_