How to reproduce:

1. Create and open a new project
2. Go to Edit → Preferences → General
3. Enable the ‘Use new Hierarchy window’ option
4. Create a few GameObjects in the Hierarchy
5. Parent some GameObjects to other GameObjects
6. Expand the parent GameObjects
7. Hold ALT and left-click the 'Pick' (hand icon) icon to the left of the parent GameObjects in the Hierarchy
8. Observe the Hierarchy

Actual result: The ‘Pick’ functionality is not toggled
Expected result: The ‘Pick’ functionality is toggled just for the parent GameObject

Reproducible in: 6000.3.0a2, 6000.3.3f1, 6000.4.0b3, 6000.5.0a4
Could not test in: 6000.0.65f1, 6000.3.0a1 (The new Hierarchy was not introduced yet)

Reproduced on: Windows 11 Pro (25H2)
Not reproduced on: No other environment tested

Notes:
- Generally, when ALT is not held, enabling ‘Pick’ on a parent GameObject enables the ‘Pick’ function of all its children GameObjects vs when AlT is held, only selected object is toggled.
- Not reproducible in the old Hierarchy