code: function(parentNode) {
          if (!parentNode) {
              return false;
          }
  
          this.tree   = parentNode.tree;
          this.parent = parentNode;
          this.depth  = parentNode.depth + 1;
  
          // @todo why was this put here.  This causes new nodes added at the
          // root level to lose the menu behavior.
          // if (! this.multiExpand) {
              // this.multiExpand = parentNode.multiExpand;
          // }
  
          this.tree.regNode(this);
          parentNode.childrenRendered = false;
  
          // cascade update existing children
          for (var i=0, len=this.children.length;i<len;++i) {
              this.children[i].applyParent(this);
          }
  
          this.fireEvent("parentChange");
  
          return true;
      }
docs: Certain properties for the node cannot be set until the parent
  is known. This is called after the node is inserted into a tree.
  the parent is also applied to this node's children in order to
  make it possible to move a branch from one tree to another.
  @method applyParent
  @param {Node} parentNode this node's parent node
  @return {boolean} true if the application was successful