import javax.swing.JFrame;

public class Main extends javax.swing.JFrame {
    
     public Main() {
        initComponents();
    }
  
@@    private void initComponents() {
        jComboBox1 = new javax.swing.JComboBox();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        jComboBox1.addPopupMenuListener(new javax.swing.event.PopupMenuListener() {
            public void popupMenuCanceled(javax.swing.event.PopupMenuEvent evt) {
                jComboBox1PopupMenuCanceled(evt);
            }
            public void popupMenuWillBecomeInvisible(javax.swing.event.PopupMenuEvent evt) {
                jComboBox1PopupMenuWillBecomeInvisible(evt);
            }
            public void popupMenuWillBecomeVisible(javax.swing.event.PopupMenuEvent evt) {
                jComboBox1PopupMenuWillBecomeVisible(evt);
            }
        });

        getContentPane().add(jComboBox1, java.awt.BorderLayout.CENTER);

        pack();
    }                        

    private void jComboBox1PopupMenuCanceled(javax.swing.event.PopupMenuEvent evt) {                                             
    System.out.println("Popup Menu Cancelled");
    }                                            

    private void jComboBox1PopupMenuWillBecomeInvisible(javax.swing.event.PopupMenuEvent evt) {                                                        
    System.out.println("Popup Menu Will Become Invisible");
    }                                                       

    private void jComboBox1PopupMenuWillBecomeVisible(javax.swing.event.PopupMenuEvent evt) {                                                      
    System.out.println("Popup Menu Will Become Visible");
    }                                                     
    
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        final JFrame frame = new Main();
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                frame.setVisible(true);
                
            }
        });
        
    }
    
    private javax.swing.JComboBox jComboBox1;
    
}