diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index efbc008..e1c8cf8 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -804,10 +804,10 @@
     accessRights = accessRights | AccessPtrEvents | AccessKeyEvents | AccessView;
     break;
   case 1:
-    accessRights = accessRights & !(AccessPtrEvents | AccessKeyEvents) | AccessView;
+    accessRights = accessRights & ~(AccessPtrEvents | AccessKeyEvents) | AccessView;
     break;
   case 2:
-    accessRights = accessRights & !(AccessPtrEvents | AccessKeyEvents | AccessView);
+    accessRights = accessRights & ~(AccessPtrEvents | AccessKeyEvents | AccessView);
     break;
   }
   framebufferUpdateRequest(server->pb->getRect(), false);