@Override
public void figureChanged(FigureEvent e) {
quadTree.remove(e.getFigure());
quadTree.add(e.getFigure(), e.getFigure().getDrawingArea());
needsSorting = true;
fireAreaInvalidated(e.getInvalidatedArea());
}
@Override
public void figureRequestRemove(FigureEvent e) {
remove(e.getFigure());
}