public static function save( $menu_id, $item_id ) {

		$popups = PUM_Modules_Menu::popup_list();

		$allowed_popups = wp_parse_id_list( array_keys( $popups ) );

		if ( ! isset( $_POST['pum-menu-editor-nonce'] ) || ! wp_verify_nonce( $_POST['pum-menu-editor-nonce'], 'pum-menu-editor-nonce' ) ) {
			return;
		}

		/**
		 * Return early if there are no settings.
		 */
		if ( empty( $_POST['menu-item-pum'][ $item_id ] ) ) {
			delete_post_meta( $item_id, '_pum_nav_item_options' );

			return;
		}

		/**
		 * Parse options array for valid keys.
		 */
		$item_options = PUM_Modules_Menu::parse_item_options( $_POST['menu-item-pum'][ $item_id ] );

		/**
		 * Check for invalid values.
		 */
		if ( ! in_array( $item_options['popup_id'], $allowed_popups ) || $item_options['popup_id'] <= 0 ) {
			unset( $item_options['popup_id'] );
		}

		/**
		 * Remove empty options to save space.
		 */
		$item_options = array_filter( $item_options );

		/**
		 * Save options or delete if empty.
		 */
		if ( ! empty( $item_options ) ) {
			update_post_meta( $item_id, '_pum_nav_item_options', $item_options );
		} else {
			delete_post_meta( $item_id, '_pum_nav_item_options' );
		}
	}