ComboBox em JInternalframe Modal

package br.com.solutec.gestor.gui;

/**
 *
 * @author  Rodrigo Rocha
 */
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.beans.*;

public class ModalInternal extends javax.swing.JInternalFrame {
    
    JPanel glass = new JPanel();

    public ModalInternal() {
      
    }

  public ModalInternal(JRootPane rootPane, Component desktop) {
   
      initComponents();
       jComboBox1.addItem("TEste");
       jComboBox1.addItem("TEste1");
       jComboBox1.addItem("TEste2");
    
    glass.setOpaque(false);

    // Attach mouse listeners
    MouseInputAdapter adapter =   new MouseInputAdapter(){};
    glass.addMouseListener(adapter);
    glass.addMouseMotionListener(adapter);

    // Define close behavior

    putClientProperty("JInternalFrame.frameType",
      "optionDialog");

    // Size frame
    Dimension size = getPreferredSize();
    Dimension rootSize = desktop.getSize();

    setBounds((rootSize.width - size.width) / 2,
              (rootSize.height - size.height) / 2,
               size.width, size.height); 
    desktop.validate(); 
    try {
      setSelected(true);
    } catch (PropertyVetoException ignored) {
    }

    // Add modal internal frame to glass pane
    glass.add(this);

    // Change glass pane to our panel
    rootPane.setGlassPane(glass);

    // Show glass pane, then modal dialog
    glass.setVisible(true);
  }

  public void setVisible(boolean value) {
    super.setVisible(value);
    if (value) {
      startModal();
    } else {
      stopModal();
    }
  }

  private synchronized void startModal() {
    try {
      if (SwingUtilities.isEventDispatchThread()) {
        EventQueue theQueue = 
          getToolkit().getSystemEventQueue();
        while (isVisible()) {
          AWTEvent event = theQueue.getNextEvent();
          Object source = event.getSource();
          if (event instanceof ActiveEvent) {
            ((ActiveEvent)event).dispatch();
          } else if (source instanceof Component) {
            ((Component)source).dispatchEvent(
              event);
          } else if (source instanceof MenuComponent) {
            ((MenuComponent)source).dispatchEvent(
              event);
          } else {
            System.err.println(
              "Unable to dispatch: " + event);
          }
        }
      } else {
        while (isVisible()) {
          wait();
        }
      }
    } catch (InterruptedException ignored) {
    }
  }

  private synchronized void stopModal() {
    notifyAll();
  }
    private void initComponents() {
        java.awt.GridBagConstraints gridBagConstraints;

        jButton1 = new javax.swing.JButton();
        jComboBox1 = new javax.swing.JComboBox();

        getContentPane().setLayout(new java.awt.GridBagLayout());

        setPreferredSize(new java.awt.Dimension(400, 300));
        jButton1.setText("jButton1");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 0;
        gridBagConstraints.gridy = 0;
        gridBagConstraints.gridheight = 2;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(11, 53, 238, 0);
        getContentPane().add(jButton1, gridBagConstraints);

        jComboBox1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox1ActionPerformed(evt);
            }
        });

        gridBagConstraints = new java.awt.GridBagConstraints();
        gridBagConstraints.gridx = 1;
        gridBagConstraints.gridy = 0;
        gridBagConstraints.anchor = java.awt.GridBagConstraints.NORTHWEST;
        gridBagConstraints.insets = new java.awt.Insets(10, 164, 0, 196);
        getContentPane().add(jComboBox1, gridBagConstraints);

        pack();
    }

    private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
       
    }                                          

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        try {
            setClosed(true);
        } catch (PropertyVetoException ignored) {
        }
        ModalInternal.this.setVisible(false);
        glass.setVisible(false);
    }                                        
    
    
    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    private javax.swing.JComboBox jComboBox1;
    // End of variables declaration
    
}