diff --git a/include/osg/Export b/include/osg/Export
index c75f8c08f..7527b40f1 100644
--- a/include/osg/Export
+++ b/include/osg/Export
@@ -24,6 +24,7 @@
 	#  define SG_EXPORT
 #endif  
 
+// set up define for whether member templates are supported by VisualStudio compilers.
 #ifdef _MSC_VER
 # if (_MSC_VER >= 1300)
 #  define __STL_MEMBER_TEMPLATES