UI Toolkit fails to render when any property in scene is modified prior to changing the Render Mode

Steps to reproduce:

1. Open the "[Internal link]" project
2. Open the "SampleScene"
3. Select the Panel Settings in the Project and set the Render Mode to "Screen Space Overlay"
4. Open Scene view
5. Edit any in-scene GameObject's Transform in any way
6. Select the Panel Settings again and in Inspector, change the Render Mode to "World Space"
7. Observe the Scene view

Actual results: The World Space UI doesn't get displayed right away

Expected results: The World Space UI is displayed right away

Reproducible with versions: 6000.6.0a6, 6000.6.0a7

Not reproducible with versions: 6000.0.77f1, 6000.3.18f1, 6000.4.12f1, 6000.5.0f1, 6000.6.0a5

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

Workaround: Change any property of any GameObject in the Scene

Notes:

• Any change to any component in the SampleScene (or saving the scene) will update the UI to display in World Space
• Entering Play Mode will start displaying the WorldSpace UI
• It appears that the regression happens only when a Theme Style Sheet is assigned to the Panel Settings