private void updateShift(int increment) {
      int maxHeight = super.preferredLayoutSize(myTarget).height - getMaxHeight();
      int newShift = Math.max(0, Math.min(maxHeight, myShift + increment));
      if (newShift != myShift) {
        myShift = newShift;
        myTarget.revalidate();
        myTarget.repaint();
        Window w = ComponentUtil.getWindow(myTarget.getComponent());
        if (w != null) {
          for (Window window : w.getOwnedWindows()) {
            window.dispose();
          }
        }
      }
    }
private void updateShift(int increment)