UI Element Hierarchy always collapses on Play Mode enter/exit when editing UXML in Context

Steps to reproduce:

1. Create and open a new project
2. Create and instantiate in the scene a new UXML file
3. Expand the Panel Renderer GameObject, select the UXML file, and open it 'in Context'
4. Add a VisualElement parent-child pair
5. Expand the parent
6. Enter Play Mode
7. Expand the parent
8. Exit Play Mode
9. Observe the Hierarchy

Actual results: On steps 6 and 8, the parent collapses

Expected results: Parent remains expanded

Reproducible with versions: 6000.6.0b5, 6000.7.0a1, 6000.7.0a3

Can’t test with versions: 6000.0.80f1, 6000.3.20f1, 6000.5.5f1, 6000.6.0a6 (can't edit 'in Context')

Tested on (OS): Windows 11 Pro (25H2)