Steps to reproduce:

1. Create a new Unity project using the Universal 3D template
2. Select the "Global Volume" GameObject in the Hierarchy window
3. Click the selection button in the "SampleSceneProfile (Volume Profile)" field in the Inspector window to open the "Select Volume Profile" window
4. Click on any other GameObject in the Hierarchy window
5. Press the duplicate shortcut (cmd+d) or the delete shortcut (cmd+delete)
6. Duplicate via the Edit menu (Edit > Duplicate)
7. Observe the Editor

Actual results: Nothing happens

Expected results: The selected GameObject is interactable and properly selected

Reproducible with versions: 6000.3.0a3, 6000.3.14f1, 6000.4.4f1, 6000.5.0b5, 6000.6.0a3

Not reproducible with versions: 6000.0.73f1, 6000.3.0a2

Tested on (OS): MacOS Silicon Tahoe 26.3

Notes:

• Reproduces with both old Hierarchy and Hierarchy v2
• In the old Hierarchy, the selected GameObject has a gray selection, but in the Hierarchy V2 the selected GameObject has a blue selection
• Regressed in the old hierarchy
• Works with different "Select" windows, whether it's Volume Profile, Texture, Texture2D, etc.

UPDATE:

The problem is more widespread than this scenario and can occur with any Window/View.

The bug occurs whenever you switch focused Views {}within the same window{}, proceed to switch focus to a completely different Window, and then click back into the original View/Window. In this case the View you clicked into isn't focused and you must click again to actually re-focus it.

For example: within the MainWindow first focus the Project View and then focus the Hierarchy,  now open and focus PackageManager (as a separate window), and finally click back into Project View. It won't be focused.

NOTE: You can identify the focused view within a window via a blue underline in the view's tab.