I am implementing a feature to allow drag/ drop between two trees. The problem is that I need to controll what can be dropped and whether. It appears that the appropriate place is to control it in the dragOver handler. I can even see in the event.currTarget that there is an internal variable _dropData with the index, but it is protected. How can I query where in the tree, the drop is plan and control where it is permissible. I would also like to do a confirmation of the details.