diff --git a/include/osgGA/SimpleViewer b/include/osgGA/SimpleViewer
index b8d3253f9..33a6dede8 100644
--- a/include/osgGA/SimpleViewer
+++ b/include/osgGA/SimpleViewer
@@ -25,7 +25,7 @@
 namespace osgGA{
 
 /** SimpleViewer provide a simple interface for setting up rendering of an scene graph, using a single camera view within a single window.*/
-class OSGGA_EXPORT SimpleViewer : public osgGA::GUIActionAdapter
+class OSGGA_EXPORT SimpleViewer : public osgGA::GUIActionAdapter, public osg::Referenced
 {
     public: