public function displayFilteringOptions(XMLElement &$wrapper)
    {
        // Add filter tags
        $filterTags = new XMLElement('ul');
        $filterTags->setAttribute('class', 'tags singular');
        $filterTags->setAttribute('data-interactive', 'data-interactive');

        $filters = $this->fetchFilterableOperators();
        foreach ($filters as $value) {
            $item = new XMLElement('li', $value['title']);
            $item->setAttribute('data-value', $value['filter']);

            if (isset($value['help'])) {
                $item->setAttribute('data-help', General::sanitize($value['help']));
            }

            $filterTags->appendChild($item);
        }
        $wrapper->appendChild($filterTags);

        $help = new XMLElement('p');
        $help->setAttribute('class', 'help');
        $first = array_shift($filters);
        $help->setValue($first['help']);
        $wrapper->appendChild($help);
    }