Index: user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user.module,v
retrieving revision 1.407.2.13
diff -U3 -r1.407.2.13 user.module
--- user.module	14 Mar 2006 01:19:55 -0000	1.407.2.13
+++ user.module	26 Apr 2006 23:38:32 -0000
@@ -794,6 +794,10 @@
 
       if (function_exists('session_regenerate_id')) {
         $old_session_id = session_id();
+        // destroy the cookie on the client to prevent the existence of two domain cookies
+        if (isset($_COOKIE[session_name()])) {
+          setcookie(session_name(), '', time()-42000, '/');
+        }
         session_regenerate_id();
         db_query("UPDATE {sessions} SET sid = '%s' WHERE sid = '%s'", session_id(), $old_session_id);      
       }