Index: includes/menu.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/menu.inc,v
retrieving revision 1.282
diff -u -p -r1.282 menu.inc
--- includes/menu.inc	10 Jul 2008 10:58:01 -0000	1.282
+++ includes/menu.inc	21 Jul 2008 14:11:47 -0000
@@ -1787,8 +1787,11 @@ function _menu_navigation_links_rebuild(
       $existing_item = db_fetch_array(db_query("SELECT mlid, menu_name, plid, customized, has_children, updated FROM {menu_links} WHERE link_path = '%s' AND module = '%s'", $item['link_path'], 'system'));
       if ($existing_item) {
         $item['mlid'] = $existing_item['mlid'];
-        $item['menu_name'] = $existing_item['menu_name'];
-        $item['plid'] = $existing_item['plid'];
+        // A change in hook_menu may move the link to a different menu
+        if (empty($item['menu_name']) || ($item['menu_name'] == $existing_item['menu_name'])) {
+          $item['menu_name'] = $existing_item['menu_name'];
+          $item['plid'] = $existing_item['plid'];
+        }
         $item['has_children'] = $existing_item['has_children'];
         $item['updated'] = $existing_item['updated'];
       }