An object in the Model pane may have one or more group assignments. When more than one group is assigned, and you want to select or hide objects by group, the disambiguator lets you pick which group to use.

For example, a single zone may have groups X, Y, and Z assigned, as well as a Building Block ID. When you show the disambiguator for that zone, you’ll see all four slot+group combinations in a list. You can click each entry in the list one by one to have the Model pane display the objects in each slot+group. After you select a slot and group in the list, you can click the Select or Hide button to act on that group.

disambiguator example