Trying out different solutions for another issue I gathered that setting XamDataGrid.FilterEvalutionMode="CollectionView" and hooking RecordFilterDropDownPopulating either in code behind or through attached property in VM you can effectively control the filter values showing up on the screen when you click on the Filter icon on a column header.

Is there a way to control the values showing up in the tree underneath 'Select All' when using MultiSelect Excel Style filters ( FilterLabelIconDropDownType="MultiSelectExcelStyle")? I see that the collection of DropDownItems is null when this mode is enabled. Instead there's some filter tree control - can its collection of nodes be assigned? Thanks.