Opening a dialog from a dropdown menu steals focus

[rogerfar]

Describe the bug

When opening a dialog from a drop down menu item, and the dialog has an input, it will focus the input, but then immediately move the focus back to the drop down menu button.

Reproduction

https://stackblitz.com/edit/vitejs-vite-fkeqqbyq?file=src%2FApp.svelte

Logs

System Info

System:
    OS: Windows 10 10.0.19045
    CPU: (24) x64 13th Gen Intel(R) Core(TM) i7-13700
    Memory: 32.53 GB / 63.79 GB
  Binaries:
    Node: 22.14.0 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.22.22 - C:\Program Files (x86)\Yarn\bin\yarn.CMD
    npm: 11.2.0 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (132.0.2957.127)
    Internet Explorer: 11.0.19041.4355

Severity

blocking an upgrade

[sproott]

I have a similar issue where I want to focus an input on the page when clicking a dropdown menu item, but the input never gets focus. I had to add around 200ms of delay before focusing the input to make it work.

[gwicki-meier]

The implementation of effect teardown was changed in Svelte 5.23. This probably causes the issue.
sveltejs/svelte#15469

Probably the same issue:
#427 (comment)