The issue occurs when creating a new resource or computer report, and then adding a new report parameter.
In this case, we selected Basic GUID Parameter for Type, and for Value Provider, we selected Resource Selector Parameter Value Edit Control.
Under Value Provider, the Resource type drop-down is blank, and there is no response when clicking OK to save the new parameter.
Release: 8.5 RU4, 8.6 RU2
Defect
This is fixed in 8.6 RU3.