Looks like we can't reproduce the issue or there's a problem in the test case provided.
Ext 4.1: Nested droptargets
Problem with nested DropTarget
I have panel A which contains two panels (B and C).
All Panels (A, B and C) are configured to be droptargets for treenodes.
I would expect that the drop event would occur on the innermost panel (in this case B or C) when I drop something on them, but the drop event occurs on the outer panel A only.
Looking at the code of DragDropManager I gather that he iterates over all droptargets and returns the first one with matching coordinates. In my case this happens always to be the outermost container.
I would expect that the inner panels get preference in receiving the drop event!