Swingのツールチップが消えない

public class Test {
  public static void main(String[] args) {
    ToolTipManager manager = ToolTipManager.sharedInstance();
    manager.setInitialDelay(0);
    manager.setDismissDelay(10000);
    manager.setReshowDelay(0);

    JLabel label = new JLabel("テスト") {
      public Point getToolTipLocation(MouseEvent event) {
        Dimension d = event.getComponent().getSize();
        Point p = new Point(0, d.height);
        return p;
      }
    };
    label.setBackground(Color.RED);
    label.setOpaque(true);
    label.setBounds(0, 0, 45, 20);
    label.setToolTipText("てすと");
    
    JFrame frame = new JFrame();
    frame.getContentPane().setLayout(null);
    frame.add(label);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 500);
    frame.setVisible(true);
  }
}

public class Test {
  public static void main(String[] args) {
    JLabel label = new JLabel("テスト") ;
    label.setBackground(Color.RED);
    label.setOpaque(true);
    label.setBounds(0, 0, 45, 20);
    label.setToolTipText("てすと");

    JFrame frame = new JFrame();
    frame.getContentPane().setLayout(null);
    frame.add(label);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 500);
    frame.setVisible(true);
  }
}