Steps to reproduce:

1. Open a Unity project
2. Open UI Builder via Window > UI Toolkit > UI Builder
3. Undock the window so that it is floating
4. Make a change so that there are unsaved changes (e.g. drag a VisualElement into the Hierarchy from the Library)
5. At the top right of the editor, press on the Layout drop-down then 'Reset All Layouts'
6. In the 'Revert All Window Layouts' pop-up window, press Continue
7. In the 'Unsaved Changes Detected' popup, press Cancel

Actual results: A 'Missing Default Layout' pop-up appears, prompting the user to either Quit or Revert Factory Settings.

Expected results: The Reset Layouts process is cancelled and the windows remain as they were.

Reproducible with versions: 

• 6000.0.13f1
• 2022.3.40f1
• 2021.3.40f1 (see notes)
• 2021.3.32f1 (see notes)

Not reproducible with versions: 

• 2021.3.31f1

Can’t test with versions: - 

Tested on (OS): Windows 10, Windows 11

Notes:

• On 2021.3, the Unsaved Changes Detected popup may display twice, so press cancel both times