Ticket #13976: 13976.diff

wp-includes/nav-menu-template.php

@@ -16 +16 @@
  */
 class Walker_Nav_Menu extends Walker {
         /**
+         * @see Walker::start_el()
+         * @since 3.0.1.
+         * @var array
+         */
+        static $_used_menu_item_ids = array();
+
+        /**
          * @see Walker::$tree_type
          * @since 3.0.0
          * @var string
@@ -66 +73 @@
          */
         function start_el(&$output, $item, $depth, $args) {
                 global $wp_query;
+
                 $indent = ( $depth ) ? str_repeat( "\t", $depth ) : '';
 
                 $class_names = $value = '';
 
                 $classes = empty( $item->classes ) ? array() : (array) $item->classes;
+                $classes[] = 'menu-item-' . $item->ID;
 
                 $class_names = join( ' ', apply_filters( 'nav_menu_css_class', array_filter( $classes ), $item ) );
                 $class_names = ' class="' . esc_attr( $class_names ) . '"';
 
-                $output .= $indent . '<li id="menu-item-'. $item->ID . '"' . $value . $class_names .'>';
+                if ( ! in_array( $item->ID, Walker_Nav_Menu::$_used_menu_item_ids ) ) {
+                        $output .= $indent . '<li id="menu-item-'. $item->ID . '"' . $value . $class_names .'>';
+                        Walker_Nav_Menu::$_used_menu_item_ids[] = $item->ID;
+                } else {
+                        $output .= $indent . '<li' . $value . $class_names .'>';
+                }
 
                 $attributes  = ! empty( $item->attr_title ) ? ' title="'  . esc_attr( $item->attr_title ) .'"' : '';
                 $attributes .= ! empty( $item->target )     ? ' target="' . esc_attr( $item->target     ) .'"' : '';