diff --git a/vncviewer/Viewport.h b/vncviewer/Viewport.h
index 14ef4ab..170be0d 100644
--- a/vncviewer/Viewport.h
+++ b/vncviewer/Viewport.h
@@ -64,6 +64,7 @@
   int handle(int event);
 
 private:
+  bool hasFocus();
 
   unsigned int getModifierMask(unsigned int keysym);