Index: /branches/release-36/lib/MT/App/CMS.pm
===================================================================
--- /branches/release-36/lib/MT/App/CMS.pm (revision 2052)
+++ /branches/release-36/lib/MT/App/CMS.pm (revision 2121)
@@ -2782,5 +2782,5 @@
     push @parts, $app->config->SecretToken;
     my $data = join ",", @parts;
-    return perl_sha1_digest_hex($data);
+    return 'mt-preview-' . perl_sha1_digest_hex($data);
 }