Index: includes/menu.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/menu.inc,v
retrieving revision 1.255.2.27
diff -u -p -r1.255.2.27 menu.inc
--- includes/menu.inc	10 Nov 2008 17:30:39 -0000	1.255.2.27
+++ includes/menu.inc	11 Dec 2008 15:42:21 -0000
@@ -1860,7 +1860,9 @@ function menu_link_save(&$item) {
   );
   $existing_item = FALSE;
   if (isset($item['mlid'])) {
-    $existing_item = db_fetch_array(db_query("SELECT * FROM {menu_links} WHERE mlid = %d", $item['mlid']));
+    if ($existing_item = db_fetch_array(db_query("SELECT * FROM {menu_links} WHERE mlid = %d", $item['mlid']))) {
+      $existing_item['options'] = unserialize($existing_item['options']);
+    }
   }
 
   if (isset($item['plid'])) {
Index: modules/menu/menu.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/menu/menu.module,v
retrieving revision 1.157.2.3
diff -u -p -r1.157.2.3 menu.module
--- modules/menu/menu.module	10 May 2008 06:53:53 -0000	1.157.2.3
+++ modules/menu/menu.module	11 Dec 2008 15:42:21 -0000
@@ -163,11 +163,13 @@ function menu_theme() {
  */
 function menu_enable() {
   menu_rebuild();
-  $link = db_fetch_array(db_query("SELECT mlid AS plid, menu_name from {menu_links} WHERE link_path = 'admin/build/menu' AND module = 'system'"));
-  $link['router_path'] = 'admin/build/menu-customize/%';
-  $link['module'] = 'menu';
+  $base_link = db_fetch_array(db_query("SELECT mlid AS plid, menu_name from {menu_links} WHERE link_path = 'admin/build/menu' AND module = 'system'"));
+  $base_link['router_path'] = 'admin/build/menu-customize/%';
+  $base_link['module'] = 'menu';
   $result = db_query("SELECT * FROM {menu_custom}");
   while ($menu = db_fetch_array($result)) {
+    // $link is passed by reference to menu_link_save(), so we make a copy of $base_link.
+    $link = $base_link;
     $link['mlid'] = 0;
     $link['link_title'] = $menu['title'];
     $link['link_path'] = 'admin/build/menu-customize/'. $menu['menu_name'];