Steps to reproduce:
1. Create new Unity project using Mixing Reality Template
2. Navigate to Assets > XR and select XRGeneralSettings.asset
3. In Inspector window expand “Keys” or “Values” drop-down
4. Try adding more Elements to the “Keys” or “Values” by pressing “” or increasing value on the right field
5. Observe the list

Actual results: nothing happens when increasing value of the list or trying to add more elements when pressing “” button, if current elements are deleted, they cannot be re-added back in the XRGeneralSettings.asset
Expected results: elements list increases when pressing “+” button or when editing the field value, if all elements are deleted, it is possible to re-add them back

Reproducible with versions: 2.2.0 (6000.0.62f1, 6000.2.11f1, 6000.3.0b9, 6000.4.0a4)

Tested on (OS): macOS Silicon, Tahoe 26.0 (M1)