diff --git a/include/osgTerrain/TerrainNode b/include/osgTerrain/TerrainNode
index d77c639a1..d72f71f6b 100644
--- a/include/osgTerrain/TerrainNode
+++ b/include/osgTerrain/TerrainNode
@@ -134,6 +134,7 @@ class OSGTERRAIN_EXPORT TerrainNode : public osg::Group
                 filter = rhs.filter;
                 layer = rhs.layer;
                 transferFunction = rhs.transferFunction;
+                return *this;
             }
 
             Filter                              filter;