diff --git a/win/vncviewer/CConn.cxx b/win/vncviewer/CConn.cxx
index aa4ba75..d5eadc4 100644
--- a/win/vncviewer/CConn.cxx
+++ b/win/vncviewer/CConn.cxx
@@ -511,6 +511,7 @@
     }
     debugRects.clear();
   }
+  window->framebufferUpdateEnd();
 
   if (firstUpdate) {
     int width, height;