Steps to reproduce:

1. Create a new Unity project using a 3D Universal Template
2. Go to Preferences > New Hierarchy
3. Make sure "Use new Hierarchy window" is enabled
4. In the Hierarchy, right-click and create an Empty GameObject
5. Create another empty GameObject as a child
6. Make sure the parent GameObject is expanded
7. Maximize any window in the Editor (except Hierarchy)
8. Unmaximize and observe the Hierarchy

Actual results: The parent GameObject is collapsed

Expected results: The parent GameObject remains in the same expanded state

Reproducible with versions: 6000.3.5f1, 6000.4.0b6, 6000.5.0a5

Can’t test with versions: 6000.0.66f1 (Hierarchy V2 not available)

Tested on (OS): macOS 26.2 (M1)

Notes:

• Does not reproduce with the old Hierarchy