How to reproduce:
1. Open the attached “IN-145749_UIbug.zip” project
2. Open Assets/test.uxml
3. Observe Viewport in the UiBuilder window
Actual result: ActionButtons inside the AppUI ActionGroup stay visible
Expected result: All children objects of the VisualElement become hidden when the parent's visibility is off
Reproducible with: 1.0.6 (6000.0.0f1), 2.2.0-pre.11 (6000.6.0a7)
Reproducible on: Windows 11 (25H2), macOS 26.5.1 M4 (by user)
Not reproducible on: No other environments tested
Note: The normal Button and Label hide correctly, UI Toolkit core visibility inheritance works. Only AppUI ActionButton/ActionGroup ignore the inherited visibility: hidden - though they do respect inherited display: none