Depth of current element.
	 * @param array  $args              Arguments.
	 * @param string $output            Passed by reference. Used to append additional content.
	 * @return null Null on failure with no changes to parameters.
	 */
	public function display_element( $element, &$children_elements, $max_depth, $depth, $args, &$output ) {
		if ( ! $element || ( 0 === $element->count && ! empty( $args[0]['hide_empty'] ) ) ) {
			return;
		}
		parent::display_element( $element, $children_elements, $max_depth, $depth, $args, $output );
	}
}