public function getListedElements ($elementType)
    {
        $allElements = $this->getAllElements($elementType);
        usort($allElements,
            function (Element $element1, Element $element2)
            {
                return strnatcasecmp($element1->getKey(), $element2->getKey());
            }
        );

        return array_filter(
            $allElements,
            function (Element $element)
            {
                return !$element->isHidden();
            }
        );
    }