[BUG] Sidebar overlaps chat area instead of resizing on expand — Claude Desktop (macOS)

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?

When the left sidebar is expanded, the chat window content is partially hidden/overlapped by the sidebar instead of the layout resizing to accommodate it. Manually resizing the app window forces a layout recalculation as a workaround.

<img width="1233" height="296" alt="Image" src="https://github.com/user-attachments/assets/16fc9b22-3742-43bf-8cd3-38f395cc4a72" />

What Should Happen?

Expected behaviour: Chat area resizes when sidebar expands

Error Messages/Logs

Actual behaviour: Sidebar overlaps the chat content

Steps to Reproduce

Steps to reproduce:

1. Open Claude Desktop on macOS
2. Expand the left sidebar
3. Observe that chat content is obscured rather than the chat area resizing

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Sonnet 4.6

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Workaround: Manually resizing the app window fixes it temporarily. However, this may present challenges on smaller screen sizes, particularly when using a multi-window view.