This example makes use of IFindUsersProcessor to filter a list of UserData users.
When dealing with objects it is a good practice to set the RfDropDown.ItemComparer parameter.
The RfDropDown uses this to determine if an item within RfDropDown.Items is selected.
By default the ItemComparer is set to:
(i1, i2) => i1?.Equals(i2)
The only time the ItemComparer does not have to be set with an object is when the list of options
stays the same. That would then allow the equals reference check to come back as true.