diff --git a/toplevel.cpp b/toplevel.cpp
index 8dbc429511..2e0b75537f 100644
--- a/toplevel.cpp
+++ b/toplevel.cpp
@@ -20,7 +20,7 @@ namespace KWin
 {
 
 Toplevel::Toplevel( Workspace* ws )
-    : vis( None )
+    : vis( NULL )
     , info( NULL )
     , client( None )
     , frame( None )