每当我用JTextField编写代码时，Swing java JComboBox就会消失。

import javax.swing.*;
import java.awt.*;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;

public class MainFrame extends JFrame {
    private JTextField textField;
    private JComboBox<String> comboBox;

    public MainFrame() {
        setTitle("JTextField and JComboBox Example");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new FlowLayout());

        textField = new JTextField(20);
        comboBox = new JComboBox<>(new String[]{"Option 1", "Option 2", "Option 3"});

        textField.addFocusListener(new FocusAdapter() {
            @Override
            public void focusLost(FocusEvent e) {
                if (!comboBox.isPopupVisible()) {
                    comboBox.showPopup();
                }
            }
        });

        add(textField);
        add(comboBox);

        pack();
        setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(MainFrame::new);
    }
}