diff --git a/common/rfb/VNCSConnectionST.h b/common/rfb/VNCSConnectionST.h
index d3bec93..9b7b14b 100644
--- a/common/rfb/VNCSConnectionST.h
+++ b/common/rfb/VNCSConnectionST.h
@@ -160,6 +160,8 @@
 
     // Internal methods
 
+    bool isShiftPressed();
+
     // Congestion control
     void writeRTTPing();
     void handleRTTPong(const struct RTTInfo &rttInfo);