diff --git a/vncviewer/Viewport.cxx b/vncviewer/Viewport.cxx
index a80b8ef..43b39d4 100644
--- a/vncviewer/Viewport.cxx
+++ b/vncviewer/Viewport.cxx
@@ -920,7 +920,7 @@
     if (window()->fullscreen_active())
       window()->fullscreen_off();
     else
-      window()->fullscreen();
+      ((DesktopWindow*)window())->fullscreen_on();
     break;
 #endif
   case ID_RESIZE: