title: Java - Look and Feel issue
body: <p>I'm having a problem with the java look and feel.</p>
  
  <p>I've set it to the Nimbus skin with the following code in my main method:</p>
  
  <pre><code>public class Main
  {
      public static void main(String[] args)
      {
          try
          {
              boolean found = false;
              for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels())
              {               
                  if ("Nimbus".equals(info.getName()))
                  {
                      UIManager.setLookAndFeel(info.getClassName());
                      found = true;
                      break;
                  }
              }
  
              if (!found) UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
              UIManager.put("AuditoryCues.playList", UIManager.get("AuditoryCues.allAuditoryCues"));
          }
          catch (Exception e) {}
  
          Manager mngr = new Manager();
          mngr.setSize(1000, 600);
          Utils.centerWindow(mngr);
          mngr.setVisible(true);
      }
  }
  </code></pre>
  
  <p>And it gives me this kind of windows:</p>
  
  <p><img src="https://i.stack.imgur.com/kw2DU.png" alt="enter image description here"></p>
  
  <p>As you can see, the JInternalFrames are correctly skinned but the main window is not!</p>
  
  <p>How can I apply the theme to this window too?</p>
  
  <p>Thanks.</p>
  
  <hr>
  
  <p><code>Manager</code> is a simple <code>JFrame</code> with the following code:</p>
  
  <pre><code>public class Manager extends JFrame
  {
      public Manager()
      {
          initComponents();
      }
  
      private void initComponents()
      {
          setDefaultCloseOperation(3);
          setTitle("My window");
          setIconImage(ImageLoader.getIcon().getImage());
  
          // My components go here
  
          pack();
      }
  }
  </code></pre>