Title: [BUG] Arrow keys do not scroll chat thread in Claude Desktop app — affects Chat, Cowork, and Code tabs (Windows)

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?

What's wrong: In the Claude Desktop app on Windows, clicking anywhere in the message thread and pressing up/down arrow keys does not scroll the conversation in any tab — Chat, Cowork, or Code. The only working method is dragging the scrollbar.
Expected behavior: Arrow keys should scroll the chat thread when focus is on the message area, across all tabs.
Platform: Windows 11 Pro (build 10.0.26200), Claude Desktop Version 1.3109.0 (35cbf6)

What Should Happen?

Arrow keys should scroll the chat thread when focus is on the message area, across all tabs.

Error Messages/Logs

Steps to Reproduce

1. Click anywhere in the chat thread
2. Attempt to use the arrow keys to scroll through the chat thread

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Code v2.1.108

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_