Pressing “+” in Style Sheet Selection Asset’s Imports list does nothing in Inspector window

Steps to reproduce:
1. Create new Unity project
2. In Project window create Style Sheet Selection Asset (right-click in Project window > Create > Style Sheet Selection)
3. In Inspector window, in “Imports” section press “+” button
 

Actual results: Pressing “+” does nothing, no items are added to the Imports list, list UI is inconsistent with other Editor windows
Expected results: Pressing “+” adds an item to the Imports list, list UI is consistent with other Editor windows

Reproducible with versions: 6000.5.0a7, 6000.5.0a8
Can’t test with versions: 6000.4.0b11 (No Style Sheet Selection available), 6000.5.0a6 (No “+” button or list available, different design)

Tested on (OS): macOS Silicon Tahoe 26.3 (M1)