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