[BUG] Popup briefly flashes at top-left before animating to correct position

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?

In claude.ai , when clicking the + button (file/image attachment) or the model selector in the chat input area, the dropdown popup briefly appears at the top-left corner of the screen for ~100-200ms before jumping to its correct position below the button.

What Should Happen?

Expected behavior: Popup appears directly at its correct position

Platform: macOS (Darwin 25.3.0)

Error Messages/Logs

Steps to Reproduce

Open Claude Code
Click the + button or the model name selector near the chat input
Observe the popup flashes at top-left first, then snaps to its correct position
if you doesnt notice then first click + to add file then instantly click model selection.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

web

Claude Code Version

latest

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_