title: JDialog isn't rendering content with no error
body: <pre><code>package gui;
  
  import java.awt.BorderLayout;
  import javax.swing.JButton;
  import javax.swing.JDialog;
  import javax.swing.JLabel;
  import javax.swing.JList;
  import javax.swing.JPanel;
  import javax.swing.JTextField;
  
  import listener.addHeaderListener;
  import listener.removeHeaderListener;
  
  public class headersGUI extends JDialog {
  public JFrame GUI;
  public JList headers;
  public JTextField name;
  public JTextField value;
  public JButton addheader;
  public JButton removeheader;
  public headersGUI(JFrame initgui){
      super(GUI, "Headers");
      GUI=initgui;
      setup();
      layout();
      this.pack();
      this.setVisible(true);
  }
  public void setup(){
      headers=new JList(GUI.headervalues);
      headers.setLayoutOrientation(JList.VERTICAL);
      name=new JTextField(10);
      value=new JTextField(10);
      addheader=new JButton("Add");
      addheader.addActionListener(new addHeaderListener(this, GUI));
      removeheader=new JButton("Remove");
      removeheader.addActionListener(new removeHeaderListener(this, GUI));
  }
  public void layout(){
      JPanel bottompanel=new JPanel();
      this.getContentPane().add(headers, BorderLayout.CENTER);
      bottompanel.add(new JLabel("Name: "));
      bottompanel.add(name);
      bottompanel.add(new JLabel("Value: "));
      bottompanel.add(value);
      bottompanel.add(addheader);
      bottompanel.add(removeheader);
      this.getContentPane().add(bottompanel, BorderLayout.SOUTH);
  }
  }
  </code></pre>
  
  <p>that is the <code>JDialog</code> code, it just shows a blank <code>JDialog</code> i am using <strong>JDK 1.5</strong> on <strong>mac OSX 10.5.8</strong></p>