public static DragGestureRecognizer registerDragListener(Component c, DragListener dragListener) {
if (dragEntryMap.containsKey(c))
return dragEntryMap.get(c).dragGestureRecognizer;
DragSource dragSource = new DragSource();
DragGestureRecognizer recognizer = dragSource.createDefaultDragGestureRecognizer(c, DnDConstants.ACTION_MOVE, dragListener);
dragSource.addDragSourceMotionListener(dragListener);
dragEntryMap.put(c, new DragEntry(recognizer, dragListener));
return recognizer;
}