关于两级JMenu中JComboBox itemListener的问题

import javax.swing.*;
import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

public class TwoLevelJMenuExample {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Two Level JMenu Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 300);

        JMenuBar menuBar = new JMenuBar();
        JMenu menu1 = new JMenu("Menu 1");
        JMenu menu2 = new JMenu("Menu 2");

        // 创建JComboBox并添加ItemListener
        JComboBox<String> comboBox = new JComboBox<>(new String[]{"Option 1", "Option 2", "Option 3"});
        comboBox.addItemListener(new ItemListener() {
            @Override
            public void itemStateChanged(ItemEvent e) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    String selectedOption = (String) comboBox.getSelectedItem();
                    System.out.println("Selected option: " + selectedOption);
                }
            }
        });

        // 将JComboBox添加到JMenu中
        menu1.add(comboBox);

        menuBar.add(menu1);
        menuBar.add(menu2);

        frame.setJMenuBar(menuBar);
        frame.setVisible(true);
    }
}