diff --git a/TTdiag.m b/TTdiag.m
index d06f2450560377bcd5cc14513d9852d8f436ee7c..1c7799ffd235f0527dfa4cd3476cb9f2fd3c2fe8 100644
--- a/TTdiag.m
+++ b/TTdiag.m
@@ -46,7 +46,7 @@ switch Action,
         catch exception
             msgbox(exception.identifier);
         end
-    case 'Delete'
+    case 'Delete',
         blockHandleTTTopMask = orig_gcbh;
         data = get_param(blockHandleTTTopMask,'UserData');
         if isempty(data)