@Override
	public synchronized void drop(DropTargetDropEvent dtde) {

		clearAutoscroll();
		if (activeDropTarget == null) {
			dtde.rejectDrop();	// MAC OSX can drop even if we told it not to in the dragOver method
			return;
		}
		activeDropTarget.drop(dtde);
	}
Combines two drop targets and sends events to them in priority order.  If the first drop target
accepts the event, then the second drop target is not accessed. 
<p>
Either of the given drop targets can be an instance of CascadedDropTarget, effectively creating 
a tree structure of drop targets.
Ghidra/Framework/Generic/src/main/java/ghidra/util/CascadedDropTarget.java