popupMenu = new JPopupMenu();
popupMenu.add(copyAction);
popupMenu.add(cutAction);
popupMenu.add(pasteAction);
popupMenu.add(refreshAction);
addMouseListener(new TreeSelectionUpdater(true));
addMouseListener(this);
addMouseMotionListener(this);
addTreeSelectionListener(this);
dragSource = DragSource.getDefaultDragSource();
DragGestureRecognizer dragGestureRecognizer = dragSource