dtde.acceptDrop(DnDConstants.ACTION_MOVE);
TreePath p = (TreePath)tr.getTransferData(flavors[i]);
Node node = (Node)p.getLastPathComponent();
YKDictionary dict = (YKDictionary)targetTree.getModel();
if (node instanceof PatternNode)
dict.addPattern((PatternNode)node, (CategoryNode)parent);
else if (node instanceof CategoryNode)
dict.addCategory((CategoryNode)node, (CategoryNode)parent);
// Last but not least, mark the drop a success.
dtde.dropComplete(true);
return;