Maybe there is something I am missing here, could you please clarify your scenario:
1. You do not see the item being dragged (the drag cue) or you do not see the item once it is dropped?
2. If you do not see the item being dropped, then could you share your DropInfo handler? I am thinking that the ItemsSource may get replaced.
3. If you are saving and retrieving the item in a single call (or without waiting for the item to be saved to the DB you may find that you are getting the result from the DB without the saved item). What I can suggest there is wait for confirmation that the item is saved before requesting the collection that contains it (I am sorry if this is not what you are doing, I am guessing a bit here).
the Telerik team