I'm creating an application that uses RadPivotMap. Its itemsource that is bound to a collection that changes based on a combobox selection. The RadPivotMap (with no GroupDefinitions) worked as I expected (the heatmap gets populated with new data). However, when I add in Group Definitions, things go wrong. The first view (with default collection) gets rendered with the proper category groupings, but when I select a new collection, the RadPivotMap just disappears. I double checked to make sure I didn't have any null Member attached to the group definition. Do you guys have any idea of what went wrong? Thanks.