code: private FilteredTreeNode createNode(final TreeNode delegateNode)
      {
          FilteredTreeNode node = new FilteredTreeNode(this, delegateNode);
          delegateToThis.put(delegateNode, node);
          thisToDelegate.put(node, delegateNode);
  
          @SuppressWarnings("unchecked")
          Enumeration<? extends TreeNode> delegateChildren = 
          delegateNode.children();
          while (delegateChildren.hasMoreElements())
          {
              TreeNode delegateChild = delegateChildren.nextElement();
              createNode(delegateChild);
          }
          return node;
      }
docs: Recursively create the node for the given delegate node and
  its children.
  
  @param delegateNode The delegate node
  @return The filtered version of the node