/**
  * @param Frame $child
  * @param bool $update_node
  *
  * @return Frame
  */
 function remove_child(Frame $child, $update_node = true)
 {
     while ($child instanceof AbstractFrameDecorator) {
         $child = $child->_frame;
     }
     return $this->_frame->remove_child($child, $update_node);
 }