No components painted when calling setVisible from another frame

Question

Hello,
I have a problem here so I could use a little help with this one.
I'm having a JFrame with a button on it. When the user clicks this button, a JDialog opens. When I call the setVisible(true) method from within the constructor of the JDialog, there is no problem. But due to some reasons (concerning modal dialog) I want to call the setVisible method from withing the actionPerformed method of the button which is located on the JFrame.
I created a little test scenario to show this behaviour:
public class Main
     public static void main(String[] args)
          new TestGUI1();
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class TestGUI1 implements ActionListener
     JFrame frame = new JFrame("Test 1");
     JPanel panel = new JPanel();
     JTextArea textarea = new JTextArea();
     JButton button = new JButton("Ok");
     public TestGUI1()
          frame.getContentPane().setLayout(new BorderLayout());
          panel.setLayout(new FlowLayout(FlowLayout.RIGHT));
          frame.getContentPane().add(panel, BorderLayout.SOUTH);
          frame.getContentPane().add(textarea, BorderLayout.CENTER);
          panel.add(button);
          button.addActionListener(this);
          frame.setSize(300,300);
          frame.setVisible(true);
     public void actionPerformed(ActionEvent e)
          if(e.getSource() == button)
               TestGUI2 tg2 = new TestGUI2(frame);
               tg2.setVisible(true);
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
public class TestGUI2 extends JDialog implements ActionListener
     JDialog dialog = new JDialog();
     JPanel panel = new JPanel();
     JTextField textfield = new JTextField(20);
     JButton button = new JButton("Close");
     public TestGUI2(JFrame frame)
          super(frame, "Test 2");
          dialog.getContentPane().setLayout(new BorderLayout());
          panel.setLayout(new FlowLayout(FlowLayout.RIGHT));
          dialog.getContentPane().add(panel, BorderLayout.SOUTH);
          dialog.getContentPane().add(textfield, BorderLayout.CENTER);
          panel.add(button);
          button.addActionListener(this);
          dialog.pack();
     public void actionPerformed(ActionEvent e)
          if(e.getSource() == button)
               dialog.dispose();
     }So when you click the 'Ok' button on the JFrame, you will see only the title of the JDialog (= Test 2). When I resize it with the mouse, then only a gray area is shown. No components visible.
What could be the reason here?
Thx

Answer 1

TestGUI2 extends JDialog, so it is a dialog, and you can call setVisible(true) on it
within TestGUI2 you create another JDialog dialog, and add all to this dialog,
which is not shown. get rid of 'dialog' and your constructor will look like this
  public TestGUI2(JFrame frame)
    super(frame, "Test 2");
    getContentPane().setLayout(new BorderLayout());
    panel.setLayout(new FlowLayout(FlowLayout.RIGHT));
    getContentPane().add(panel, BorderLayout.SOUTH);
    getContentPane().add(textfield, BorderLayout.CENTER);
    panel.add(button);
    button.addActionListener(this);
    pack();
    }