public function contentCollapseIcon(
        array &$data,
        $sortField,
        $level,
        &$contentCollapseIcon,
        DatabaseRecordListXclass $parentObj
    ) {
        if ($data['_EXPAND_TABLE_'] === 'tt_content') {
            $expandTitle = $this->languageService->sL('LLL:EXT:gridelements/Resources/Private/Language/locallang_db.xlf:list.expandElement');
            $collapseTitle = $this->languageService->sL('LLL:EXT:gridelements/Resources/Private/Language/locallang_db.xlf:list.collapseElement');
            $expandedGridelements = $parentObj->getExpandedGridelements();
            if ($expandedGridelements[$data['uid']]) {
                $href = htmlspecialchars(($parentObj->listURL() . '&gridelementsExpand[' . (int)$data['uid'] . ']=0'));
                $contentCollapseIcon = '<a class="btn btn-default t3js-toggle-gridelements-list open-gridelements-container" data-state="expanded" href="' . $href .
                    '" id="t3-gridelements-' . $data['uid'] . '" title="' . $collapseTitle
                    . '" data-toggle-title="' . $expandTitle . '">'
                    . $this->getIconFactory()->getIcon('actions-view-list-expand', 'small')->render()
                    . $this->getIconFactory()->getIcon('actions-view-list-collapse', 'small')->render() . '</a>';
            } else {
                $href = htmlspecialchars(($parentObj->listURL() . '&gridelementsExpand[' . (int)$data['uid'] . ']=1'));
                $contentCollapseIcon = '<a class="btn btn-default t3js-toggle-gridelements-list" data-state="collapsed" href="' . $href .
                    '" id="t3-gridelements-' . $data['uid'] . '" title="' . $expandTitle
                    . '" data-toggle-title="' . $collapseTitle . '">'
                    . $this->getIconFactory()->getIcon('actions-view-list-expand', 'small')->render()
                    . $this->getIconFactory()->getIcon('actions-view-list-collapse', 'small')->render() . '</a>';
            }
        }
    }