I've attached an image which hopefully helps me to better describe my issue:
I need to enable drag and drop only for and within a single tree item.
So each content element within a tree item should only be drag-&dropable within the same item.
The tree items itself ( cars, trucks, etc.) shoudn't be draggable at all.
I'm having trouble to prevent a content drag&drop operation from one tree item to another one ( e.g (2) => (3)).
I would be glad for some help.
Thanks in advance