Sorry for my bad english.
I have ObservableCollection which is binded to RadJumpList.
If I open group picker items and then modify the ObservableCollection,it seems group picker items not updated according to collection.
I found workaround (uncomment //RefreshGroupPickerItemsSource(); in button click event handler, source code is attached to this message), but I think this bug should be fixed.
See this bug on video: http://youtu.be/2_qJyni6748