Steps to reproduce:
1. Create new Unity project using High Definition 3D Template
2. Create a new Scene in Project window (Create > Scene > Scene)
3. Open New Scene
4. Open Game View tab
5. In Hierarchy window select Main Camera
6. In Inspector window find “Environment”
7. Change Background Type from “Sky” to “Color”
Observe Game View window
8. Move mouse to Game view window
9. Observe Game View
Actual results: Game view does not refresh after changing Background Type, only when mouse if moved on it
Expected results: Game view should change after changing Background Type
Reproducible with versions: 6000.0.65f1, 6000.3.4f1, 6000.4.0b4, 6000.5.0a1
Not reproducible with versions: 6000.5.0a2, 6000.5.0a4
Tested on (OS): macOS Silicon Tahoe 26.2 (M1)