public function removeItemsFromListOfSelectableContainers(array &$params, array &$possibleContainers)
    {
        $contentType = is_array($params['row']['CType']) ? $params['row']['CType'][0] : $params['row']['CType'];
        if ($contentType === 'gridelements_pi1' && count($params['items']) > 1) {
            $items = $params['items'];
            $params['items'] = [0 => array_shift($items)];

            foreach ($items as $item) {
                $possibleContainers[$item['1']] = $item;
            }

            if ($params['row']['uid'] > 0) {
                $this->lookForChildContainersRecursively((int)$params['row']['uid'], $possibleContainers);
            }
        }
    }