public function updateRightValues($first, $last, $delta, $rootVal=null)
    {
        $hasManyRoots = $this->getConfiguration()->hasManyRoots();

        foreach($this->wrappers as $wrapper)
        {
            if(!$hasManyRoots || ($wrapper->getRootValue() == $rootVal))
            {
                if($wrapper->getRightValue() >= $first && ($last === 0 || $wrapper->getRightValue() <= $last))
                {
                    $wrapper->setRightValue($wrapper->getRightValue() + $delta);
                    $wrapper->invalidate();
                }
            }
        }
    }