How to reproduce:
1. Open the attached “IN-142676_rVE” project
2. Open the “SampleScene” scene
3. Enter Play mode
4. In the Hierarchy window, select the “UIDocument” GameObject and then select the “GameObject” GameObject.
5. Repeat step 4 a couple of times.
6. Observe the Console window.
Actual result: On each new selection of the “UIDocument” GameObject, these log messages are thrown: “[Probe] FRAME … (hooked@1): DETACH originPanel=set destinationPanel=null”, “[Probe] FRAME …: rootVisualElement CHANGED. old=… new=…”
Expected result: Only these log messages should be thrown when entering Play mode: “[Probe] OnEnable rootHash=…”, and when leaving Play mode: “[Probe] FRAME … (hooked@0): DETACH originPanel=set destinationPanel=null”.
Reproducible with: 6000.3.16f1, 6000.4.0a2 (79bd4f638ac0), 6000.4.8f1, 6000.5.0b8, 6000.6.0a5
Not reproducible with: 6000.0.77f1, 6000.4.0a1
Fixed in: 6000.3.17f1, 6000.4.9f1, 6000.5.0b9, 6000.6.0a6
Reproducible on: Windows 11, macOS (M4) (26.5)
Not reproducible on: No other environments tested.
Note: The issue does not reproduce when the Inspector window is closed or the UIDocument has an assigned Source Asset.