public void setFirstComponent(@Nullable JComponent component) {
    if (myFirstComponent != component) {
      if (myFirstComponent != null) {
        remove(myFirstComponent);
      }
      myFirstComponent = component;
      if (myFirstComponent != null) {
        super.add(myFirstComponent);
      }
      revalidate();
      repaint();
    }
  }
public void setFirstComponent(@Nullable JComponent component)