How to reproduce:
1. Open the attached project "UIToolkitCanvas"
2. Open the "Test" UI Document
3. Make sure the "Canvas Background" is selected in the .uxml Inspector
4. Click in the Canvas area to select the "Visual Element"
5. Enable and disable the "Preview"
6. Click anything else in the UI Builder and observe the results
Expected results: The "Visual Element" bounds are not blue
Actual results: The "Visual Element" bounds remain blue
Reproducible with: 6000.0.63f1, 6000.2.14f1, 6000.3.0b10, 6000.4.0a5, 6000.5.0a2
Reproducible on: macOS Tahoe 26 (M1)
Not reproducible on: No other environment tested
Note: The selection disappears when hovered on the "Visual Element" in the Hierarchy