UXML asset changes become not synced on multiple UI Builder windows after UI Builder window was maximized

Steps to reproduce:

1. Open the attached project
2. Open the New UXML asset in both UI Builder windows
3. Make some changes to UXML - observe that changes appear on both windows as expected
4. Save the Changes
5. Maximise and un-maximise one of the UI Builder windows
6. Make changes to the UXML asset from both UI Builder windows

Actual results: Changes are no longer synced between the two UI Builder windows

Expected results: Changes made to the UXML asset remain synced as in step 3

 

Reproducible with versions: 6000.7.0a6

Can’t test with versions: 6000.7.0a5 and earlier (Multiple UI Builder windows not supported)

Tested on (OS): macOS 26.6.2, Ubuntu 24