Typed Drag'n'drop. Some nodes from firstTree have disabled actions.

firstTree. Between DND mode. Accepts firstTree only.

Item 1
Item 1.1

Item 1.2
Item 1.2.1
Item 1.2.2
Can't add child to this node
Empty folder
Item 1.3.2
Item 1.4
Item 1.4.1
Can't move this node

secondTree. Onto DND mode. Accepts firstTree and secondTree.

Node 1
Node 2
Node 2.1
Node 2.2