title: How to add tree to tab in bean
body: <p>I try to add tree to 1 tab:</p>
  
  <pre><code>Tab tmp = new Tab();
  TreeNode root = new  DefaultTreeNode("root",null);
  TreeNode test = new DefaultTreeNode("test",root);
  tmp.getChildren().add((UIComponent)root);
  </code></pre>
  
  <p>can anyone help me?</p>