diff -r 5bd6c7671c9e -r 2bfbe3f4307c src/lemon/list_graph.h
--- a/src/lemon/list_graph.h	Sat Nov 20 10:19:06 2004 +0000
+++ b/src/lemon/list_graph.h	Sat Nov 20 11:10:56 2004 +0000
@@ -399,8 +399,8 @@
     ///\warning Edge and node deletions cannot be restored.
     ///\warning SnapShots cannot be nested.
     ///\ingroup graphs
-    class SnapShot : public AlterationObserverRegistry<Node>::ObserverBase,
-		     public AlterationObserverRegistry<Edge>::ObserverBase
+    class SnapShot : protected AlterationObserverRegistry<Node>::ObserverBase,
+		     protected AlterationObserverRegistry<Edge>::ObserverBase
     {
       protected: