diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index c63e6b6..49975cb 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -1058,7 +1058,7 @@
 
     // The request might be for just part of the screen, so we cannot
     // just clear the entire update tracker.
-    updates.subtract(requested);
+    updates.subtract(req);
 
     requested.clear();
   }