svoid addMouseListener_inFront(JComponent c, MouseListener listener) {
  if (c == null || listener == null) ret;
  swing {
    var otherListeners = c.getListeners(MouseListener.class);
    fOr (MouseListener l : otherListeners)
      c.removeMouseListener(l);
    c.addMouseListener(listener);
    fOr (MouseListener l : otherListeners)
      c.addMouseListener(l);
  }
}