Index: wp-admin/admin-ajax.php
===================================================================
--- wp-admin/admin-ajax.php	(revision 17979)
+++ wp-admin/admin-ajax.php	(working copy)
@@ -784,12 +784,14 @@
 	if ( is_wp_error( $item_ids ) )
 		die('-1');
 
+	$post_parent_ids = array();
 	foreach ( (array) $item_ids as $menu_item_id ) {
 		$menu_obj = get_post( $menu_item_id );
 		if ( ! empty( $menu_obj->ID ) ) {
 			$menu_obj = wp_setup_nav_menu_item( $menu_obj );
 			$menu_obj->label = $menu_obj->title; // don't show "(pending)" in ajax-added items
 			$menu_items[] = $menu_obj;
+			$post_parent_ids[$menu_obj->object_id] = $menu_obj->db_id;
 		}
 	}
 
@@ -799,7 +801,7 @@
 			'before' => '',
 			'link_after' => '',
 			'link_before' => '',
-			'walker' => new Walker_Nav_Menu_Edit,
+			'walker' => new Walker_Nav_Menu_Edit( array( 'id' => 'object_id', 'parent' => 'post_parent', 'parent_ids' => $post_parent_ids ) ),
 		);
 		echo walk_nav_menu_tree( $menu_items, 0, (object) $args );
 	}
Index: wp-admin/includes/nav-menu.php
===================================================================
--- wp-admin/includes/nav-menu.php	(revision 17979)
+++ wp-admin/includes/nav-menu.php	(working copy)
@@ -8,6 +8,12 @@
  * @uses Walker_Nav_Menu
  */
 class Walker_Nav_Menu_Edit extends Walker_Nav_Menu  {
+	
+	function __construct( $fields = false ) {
+		if ( $fields )
+			$this->db_fields = $fields;
+	}
+	
 	/**
 	 * @see Walker_Nav_Menu::start_lvl()
 	 * @since 3.0.0
@@ -74,6 +80,13 @@
 		}
 
 		$title = empty( $item->label ) ? $title : $item->label;
+		if ( $this->db_fields['parent'] == 'menu_item_parent' ) {
+			$menu_item_parent = $item->menu_item_parent;
+		} else if ( isset( $this->db_fields['parent_ids'][$item->post_parent] ) ) {
+			$menu_item_parent = $this->db_fields['parent_ids'][$item->post_parent];
+		} else {
+			$menu_item_parent = 0;
+		}
 
 		?>
 		<li id="menu-item-<?php echo $item_id; ?>" class="<?php echo implode(' ', $classes ); ?>">
@@ -189,7 +202,7 @@
 				<input class="menu-item-data-db-id" type="hidden" name="menu-item-db-id[<?php echo $item_id; ?>]" value="<?php echo $item_id; ?>" />
 				<input class="menu-item-data-object-id" type="hidden" name="menu-item-object-id[<?php echo $item_id; ?>]" value="<?php echo esc_attr( $item->object_id ); ?>" />
 				<input class="menu-item-data-object" type="hidden" name="menu-item-object[<?php echo $item_id; ?>]" value="<?php echo esc_attr( $item->object ); ?>" />
-				<input class="menu-item-data-parent-id" type="hidden" name="menu-item-parent-id[<?php echo $item_id; ?>]" value="<?php echo esc_attr( $item->menu_item_parent ); ?>" />
+				<input class="menu-item-data-parent-id" type="hidden" name="menu-item-parent-id[<?php echo $item_id; ?>]" value="<?php echo esc_attr( $menu_item_parent ); ?>" />
 				<input class="menu-item-data-position" type="hidden" name="menu-item-position[<?php echo $item_id; ?>]" value="<?php echo esc_attr( $item->menu_order ); ?>" />
 				<input class="menu-item-data-type" type="hidden" name="menu-item-type[<?php echo $item_id; ?>]" value="<?php echo esc_attr( $item->type ); ?>" />
 			</div><!-- .menu-item-settings-->