diff --git a/VistaCoreLibs/VistaAspects/VistaObserver.h b/VistaCoreLibs/VistaAspects/VistaObserver.h
index ecb6d21468f84b1e4b2bd8465baa6e548439e740..8b575da504694c8c2a4255da2087313f624a06da 100644
--- a/VistaCoreLibs/VistaAspects/VistaObserver.h
+++ b/VistaCoreLibs/VistaAspects/VistaObserver.h
@@ -164,7 +164,7 @@ private:
 class VISTAASPECTSAPI VistaSimpleObserver : public IVistaObserver
 {
 public:
-	std::function< void( IVistaObserveable*, int, int ) > ObserverUpdateFunc;
+	typedef std::function< void( IVistaObserveable*, int, int ) > ObserverUpdateFunc;
 
 public:
 	VistaSimpleObserver( ObserverUpdateFunc fnObserverUpdate );