Adding drag'n'drop in treeview plugin (by Jörn Zaefferer)

Adding drag'n'drop in treeview plugin (by Jörn Zaefferer)

Hi all !
Sorry for my english ...
I try to add the drag'n'drop event on the treeviw plug-in by Jörn Zaefferer but i have a problem.
I work in async mode.
In attachment you can find my code.
The drag&drop is in the applyEvent function.
but the problem is that when i try to drag & drop an item who are in the link 3.6 (this item is lazy load) the drop function are run two times , it's very strange ...
Maybe the problem come from the drag&drop function ... but i'm not sure !
I do not know any more what to make...
I contacted Jörn Zaefferer too and he must see in a next day....
Maybe you can help me ? please
Best regards,
Arthur Barbaray