 controls works pretty much the same way as it
does for internally dragging within a control, because you can determine
the node being dragged from the drag-drop data from any instance of the TreeView
control.  The only difference is that you can will also now want to start checking 
the source of the dragged node to see if it is appropriate to drop it at the target 
location.
</p><p>
The <span class="code">Owner</span> property of a node can be used for this purpose.
This returns the control that owns the 