[BUG] UI glitch in Claude macOS 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?

I downloaded the Cloud app yesterday and I saw a UI glitch in it where next to the sidebar, a rectangular overlay shows up and hides half the app. When I started to experience this problem, I reached out to the help AI assistant, and I tried a bunch of different things, including resizing the window, clearing cache, and a couple of other things it showed me, but it didn't work. I made sure that I have the latest macOS and the latest Cloud app. I even deleted the app and re-downloaded it again today, but I'm still having the same issue. The screenshot is attached and the overlay only shows up when the sidebar is on and open, and it goes away when the sidebar has been toggled off.​ It happens across chat, cowork and code. This is the first time I am using the app so it's not a "new" issue. Just always happened since I tried yesterday.

<img width="1107" height="765" alt="Image" src="https://github.com/user-attachments/assets/6b5146cf-1274-4f54-881b-79ae4d1d7297" />

What Should Happen?

I should have to deal with the strange redering overlay which takes over half the screen of the app

Error Messages/Logs

Steps to Reproduce

Downloaded the app and opened it - twice. same thing happens.

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.111

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_