diff --git a/wp-admin/admin-ajax.php b/wp-admin/admin-ajax.php
index 7d05ab1cc7..3341fd6792 100644
--- a/wp-admin/admin-ajax.php
+++ b/wp-admin/admin-ajax.php
@@ -827,6 +827,8 @@ case 'add-menu-item' :
 	$menu_id = (int) $_POST['menu'];
 	if ( isset( $_POST['menu-item'] ) ) {
 		$item_ids = wp_save_nav_menu_item( $menu_id, $_POST['menu-item'] );
+		if ( is_wp_error( $item_ids ) ) 
+			die('-1');
 	} else {
 		$item_ids = array();
 	}
diff --git a/wp-admin/includes/nav-menu.php b/wp-admin/includes/nav-menu.php
index 6e1584c864..1914509615 100644
--- a/wp-admin/includes/nav-menu.php
+++ b/wp-admin/includes/nav-menu.php
@@ -808,7 +808,7 @@ function wp_nav_menu_item_taxonomy_meta_box( $object, $taxonomy ) {
  *
  * @param int $menu_id The menu ID for which to save this item.
  * @param array $menu_data The unsanitized posted menu item data.
- * @return array The database IDs of the items saved.
+ * @return array The database IDs of the items saved
  */
 function wp_save_nav_menu_item( $menu_id = 0, $menu_data = array() ) {
 	$menu_id = (int) $menu_id;
diff --git a/wp-admin/nav-menus.php b/wp-admin/nav-menus.php
index d49fbe61ed..db0fcc9ca7 100644
--- a/wp-admin/nav-menus.php
+++ b/wp-admin/nav-menus.php
@@ -38,7 +38,7 @@ wp_enqueue_script( 'wp-lists' );
 wp_enqueue_script( 'postbox' );
 
 // Container for any messages displayed to the user
-$messages_div = '';
+$messages = array();
 
 // Container that stores the name of the active menu
 $nav_menu_selected_title = '';
@@ -169,7 +169,7 @@ switch ( $action ) {
 		if ( is_nav_menu_item( $menu_item_id ) ) {
 			if ( wp_delete_post( $menu_item_id, true ) ) {
 				
-				$messages_div = '<div id="message" class="updated"><p>' . __('The menu item has been successfully deleted.') . '</p></div>';
+				$messages[] = '<div id="message" class="updated"><p>' . __('The menu item has been successfully deleted.') . '</p></div>';
 			}
 		}
 		break;
@@ -180,9 +180,9 @@ switch ( $action ) {
 			$delete_nav_menu = wp_delete_nav_menu( $nav_menu_selected_id );
 
 			if ( is_wp_error($delete_nav_menu) ) {
-				$messages_div = '<div id="message" class="error"><p>' . $delete_nav_menu->get_error_message() . '</p></div>';
+				$messages[] = '<div id="message" class="error"><p>' . $delete_nav_menu->get_error_message() . '</p></div>';
 			} else {
-				$messages_div = '<div id="message" class="updated"><p>' . __('The menu has been successfully deleted.') . '</p></div>';
+				$messages[] = '<div id="message" class="updated"><p>' . __('The menu has been successfully deleted.') . '</p></div>';
 				$nav_menu_selected_id = 0; // Reset the selected menu
 			}
 			unset( $delete_nav_menu );
@@ -201,15 +201,15 @@ switch ( $action ) {
 					$_nav_menu_selected_id = wp_update_nav_menu_object( 0, array('menu-name' => $new_menu_title) );
 
 					if ( is_wp_error( $_nav_menu_selected_id ) ) {
-						$messages_div = '<div id="message" class="error"><p>' . $_nav_menu_selected_id->get_error_message() . '</p></div>';
+						$messages[] = '<div id="message" class="error"><p>' . $_nav_menu_selected_id->get_error_message() . '</p></div>';
 					} else {
 						$_menu_object = wp_get_nav_menu_object( $_nav_menu_selected_id );
 						$nav_menu_selected_id = $_nav_menu_selected_id;
 						$nav_menu_selected_title = $_menu_object->name;
-						$messages_div = '<div id="message" class="updated"><p>' . sprintf( __('The <strong>%s</strong> menu has been successfully created.'), $nav_menu_selected_title ) . '</p></div>';
+						$messages[] = '<div id="message" class="updated"><p>' . sprintf( __('The <strong>%s</strong> menu has been successfully created.'), $nav_menu_selected_title ) . '</p></div>';
 					}
 				} else {
-					$messages_div = '<div id="message" class="error"><p>' . __('Please enter a valid menu name.') . '</p></div>';
+					$messages[] = '<div id="message" class="error"><p>' . __('Please enter a valid menu name.') . '</p></div>';
 				}
 			}
 
@@ -222,7 +222,7 @@ switch ( $action ) {
 				$_nav_menu_selected_id = wp_update_nav_menu_object( $nav_menu_selected_id, array( 'menu-name' => $_POST['menu-name'] ) );
 				if ( is_wp_error( $_nav_menu_selected_id ) ) {
 					$_menu_object = $_nav_menu_selected_id;
-					$messages_div = '<div id="message" class="error"><p>' . $_nav_menu_selected_id->get_error_message() . '</p></div>';
+					$messages[] = '<div id="message" class="error"><p>' . $_nav_menu_selected_id->get_error_message() . '</p></div>';
 				} else {
 					$_menu_object = wp_get_nav_menu_object( $_nav_menu_selected_id );
 					$nav_menu_selected_title = $_menu_object->name;
@@ -248,9 +248,10 @@ switch ( $action ) {
 
 						$menu_item_db_id = wp_update_nav_menu_item( $nav_menu_selected_id, ( $_POST['menu-item-db-id'][$_key] != $_key ? 0 : $_key ), $args );
 
-						if ( ! is_wp_error( $menu_item_db_id ) && isset( $menu_items[$menu_item_db_id] ) ) {
+						if ( is_wp_error( $menu_item_db_id ) ) 
+							$messages[] = '<div id="message" class="error"><p>' . $menu_item_db_id->get_error_message() . '</p></div>';
+						elseif ( isset( $menu_items[$menu_item_db_id] ) )
 							unset( $menu_items[$menu_item_db_id] );
-						}
 					}
 				}
 
@@ -265,7 +266,7 @@ switch ( $action ) {
 
 				do_action( 'wp_update_nav_menu', $nav_menu_selected_id );
 
-				$messages_div = '<div id="message" class="updated"><p>' . sprintf( __('The <strong>%s</strong> menu has been updated.'), $nav_menu_selected_title ) . '</p></div>';
+				$messages[] = '<div id="message" class="updated"><p>' . sprintf( __('The <strong>%s</strong> menu has been updated.'), $nav_menu_selected_title ) . '</p></div>';
 				unset( $menu_items );
 			}
 		}
@@ -310,12 +311,12 @@ if ( current_theme_supports('nav-menus') ) {
 } elseif ( current_theme_supports('widgets') ) {
 	// Set up nav menu
 	wp_nav_menu_setup();
-	$messages_div = '<div id="message" class="error"><p>' . __('The current theme does not natively support menus, but you can use the &#8220;Navigation Menu&#8221; widget to add any menus you create here to the theme&#8217;s sidebar.') . '</p></div>';
+	$messages[] = '<div id="message" class="error"><p>' . __('The current theme does not natively support menus, but you can use the &#8220;Navigation Menu&#8221; widget to add any menus you create here to the theme&#8217;s sidebar.') . '</p></div>';
 
 // The theme supports neither menus nor widgets.
 } else {
 	remove_meta_box( 'create-menu', 'nav-menus', 'side' );
-	$messages_div = '<div id="message" class="error"><p>' . __('The current theme does not support menus.') . '</p></div>';
+	$messages[] = '<div id="message" class="error"><p>' . __('The current theme does not support menus.') . '</p></div>';
 }
 
 // Get the admin header
@@ -324,7 +325,11 @@ require_once( 'admin-header.php' );
 <div class="wrap">
 	<?php screen_icon(); ?>
 	<h2><?php esc_html_e('Menus'); ?></h2>
-	<?php echo $messages_div; ?>
+	<?php 
+	foreach( $messages as $message ) :
+		echo $message . "\n"; 
+	endforeach;
+	?>
 	
 	<?php if ( current_theme_supports('nav-menus') || current_theme_supports('widgets') ) : ?>
 	<div id="nav-menus-frame">
diff --git a/wp-includes/default-filters.php b/wp-includes/default-filters.php
index dcbadb0b0a..135c4a079d 100644
--- a/wp-includes/default-filters.php
+++ b/wp-includes/default-filters.php
@@ -224,7 +224,11 @@ add_action( 'publish_post',               '_publish_post_hook',       5, 1 );
 add_action( 'save_post',                  '_save_post_hook',          5, 2 );
 add_action( 'transition_post_status',     '_transition_post_status',  5, 3 );
 add_action( 'comment_form', 'wp_comment_form_unfiltered_html_nonce'        );
-add_action( 'wp_scheduled_delete',        'wp_scheduled_delete' );
+add_action( 'wp_scheduled_delete',        'wp_scheduled_delete'            );
+add_action( 'trash_post',                 '_wp_trash_menu_item'            );
+add_action( 'untrash_post',               '_wp_untrash_menu_item'          );
+add_action( 'delete_post',                '_wp_delete_post_menu_item'      );
+add_action( 'delete_term',                '_wp_delete_tax_menu_item'       );
 
 // Post Thumbnail CSS class filtering
 add_action( 'begin_fetch_post_thumbnail_html', '_wp_post_thumbnail_class_filter_add'    );
diff --git a/wp-includes/nav-menu.php b/wp-includes/nav-menu.php
index 94548915be..aff786de56 100644
--- a/wp-includes/nav-menu.php
+++ b/wp-includes/nav-menu.php
@@ -268,8 +268,17 @@ function wp_update_nav_menu_item( $menu_id = 0, $menu_item_db_id = 0, $menu_item
 		if ( 'taxonomy' == $args['menu-item-type'] ) {
 			$original_title = get_term_field( 'name', $args['menu-item-object-id'], $args['menu-item-object'], 'raw' );
 		} elseif ( 'post_type' == $args['menu-item-type'] ) {
+
 			$original_object = get_post( $args['menu-item-object-id'] );
 			$original_title = $original_object->post_title;
+
+			if ( 'trash' == get_post_status( $args['menu-item-object-id'] ) ) {
+				$post_type_object = get_post_type_object( $args['menu-item-object'] );
+				if ( isset( $post_type_object->singular_label ) )
+					return new WP_Error('update_nav_menu_item_failed', sprintf(__('The menu item "%1$s" belongs to a %2$s that is in the trash, so it cannot be updated.'), $args['menu-item-title'], $post_type_object->singular_label ) );
+				else
+					return new WP_Error('update_nav_menu_item_failed', sprintf(__('The menu item "%1$s" belongs to something that is in the trash, so it cannot be updated.'), $args['menu-item-title'] ) );
+			}
 		}
 
 		if ( empty( $args['menu-item-title'] ) || $args['menu-item-title'] == $original_title ) {
@@ -528,4 +537,120 @@ function wp_setup_nav_menu_item( $menu_item ) {
 
 	return apply_filters( 'wp_setup_nav_menu_item', $menu_item );
 }
+
+/**
+ * Get the menu items associated with a particular object.
+ *
+ * @since 3.0.0
+ * 
+ * @param int $object_id The ID of the original object.
+ * @param string $object_type The type of object, such as "taxonomy" or "post_type."
+ * @return array The array of menu item IDs; empty array if none;
+ */
+function wp_get_associated_nav_menu_items( $object_id = 0, $object_type = 'post_type' ) {
+	$object_id = (int) $object_id;
+	$menu_item_ids = array();
+
+	$query = new WP_Query;
+	$menu_items = $query->query(
+		array(
+			'meta_key' => '_menu_item_object_id',
+			'meta_value' => $object_id,
+			'post_status' => 'any',
+			'post_type' => 'nav_menu_item',
+			'showposts' => -1,
+		)
+	);
+	foreach( (array) $menu_items as $menu_item ) {
+		if ( isset( $menu_item->ID ) && is_nav_menu_item( $menu_item->ID ) ) {
+			if ( get_post_meta($menu_item->ID, '_menu_item_type', true) != $object_type )
+				continue;
+
+			$menu_item_ids[] = (int) $menu_item->ID;
+		}
+	}
+
+	return array_unique( $menu_item_ids );
+}
+
+/**
+ * Callback for handling a menu item when its original object is trashed.
+ *
+ * @since 3.0.0
+ * @access private
+ *
+ * @param int $object_id The ID of the original object being trashed.
+ *
+ */
+function _wp_trash_menu_item( $object_id = 0 ) {
+	$object_id = (int) $object_id;
+
+	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id );
+
+	foreach( (array) $menu_item_ids as $menu_item_id ) {
+		$menu_item = get_post( $menu_item_id, ARRAY_A );
+		$menu_item['post_status'] = 'draft';
+		wp_insert_post($menu_item);
+	}
+}
+
+/**
+ * Callback for handling a menu item when its original object is un-trashed.
+ *
+ * @since 3.0.0
+ * @access private
+ *
+ * @param int $object_id The ID of the original object being untrashed.
+ *
+ */
+function _wp_untrash_menu_item( $object_id = 0 ) {
+	$object_id = (int) $object_id;
+
+	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id );
+
+	foreach( (array) $menu_item_ids as $menu_item_id ) {
+		$menu_item = get_post( $menu_item_id, ARRAY_A );
+		$menu_item['post_status'] = 'publish';
+		wp_insert_post($menu_item);
+	}
+}
+
+/**
+ * Callback for handling a menu item when its original object is deleted.
+ *
+ * @since 3.0.0
+ * @access private
+ *
+ * @param int $object_id The ID of the original object being trashed.
+ *
+ */
+function _wp_delete_post_menu_item( $object_id = 0 ) {
+	$object_id = (int) $object_id;
+
+	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id, 'post_type' );
+
+	foreach( (array) $menu_item_ids as $menu_item_id ) {
+		wp_delete_post( $menu_item_id, true );
+	}
+}
+
+/**
+ * Callback for handling a menu item when its original object is deleted.
+ *
+ * @since 3.0.0
+ * @access private
+ *
+ * @param int $object_id The ID of the original object being trashed.
+ *
+ */
+function _wp_delete_tax_menu_item( $object_id = 0 ) {
+	$object_id = (int) $object_id;
+
+	$menu_item_ids = wp_get_associated_nav_menu_items( $object_id, 'taxonomy' );
+
+	foreach( (array) $menu_item_ids as $menu_item_id ) {
+		wp_delete_post( $menu_item_id, true );
+	}
+}
+
 ?>
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 2674f70eee..a0f46ad3bb 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -2167,7 +2167,7 @@ function wp_insert_post($postarr = array(), $wp_error = false) {
 		} elseif ( !empty($post_parent) ) {
 			$parent_post = get_post($post_parent);
 			// Check for circular dependency
-			if ( $parent_post->post_parent == $post_ID )
+			if ( isset( $parent_post->post_parent ) && $parent_post->post_parent == $post_ID )
 				$post_parent = 0;
 		}
 	}