Sorry for the delayed reply. Dropping an item onto itself or onto its father RadTreeViewItem or onto its children RadTreeViewitems (direct or not) is an invalid drop operation which does not fire the RadTreeView.PreviewDragEnded event. Therefore you cannot use the default RadTreeView drag and drop logic. You can use a DragAndDropManager and its events to implement adding a copy of the dragged RadTreeViewItem to the specific locations mentioned above. For the other drop locations you can handle the PreviewDragEnded event. Please find the attached solution which demonstrates such functionality and tell me if it satisfies your needs.
I hope this is helpful for you. Feel free to ask if you need further assistance.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items