diff --git a/vncviewer/parameters.h b/vncviewer/parameters.h
index df4b080..77c5ae9 100644
--- a/vncviewer/parameters.h
+++ b/vncviewer/parameters.h
@@ -50,4 +50,6 @@
 
 extern rfb::StringParameter menuKey;
 
+extern rfb::BoolParameter fullscreenSystemKeys;
+
 #endif