1.1 --- a/lemon/bits/edge_set_extender.h	Tue Dec 20 17:36:41 2011 +0100
     1.2 +++ b/lemon/bits/edge_set_extender.h	Tue Dec 20 17:38:19 2011 +0100
     1.3 @@ -280,6 +280,8 @@
     1.4  
     1.5      typedef EdgeSetExtender Graph;
     1.6  
     1.7 +    typedef True UndirectedTag;
     1.8 +
     1.9      typedef typename Parent::Node Node;
    1.10      typedef typename Parent::Arc Arc;
    1.11      typedef typename Parent::Edge Edge;

     2.1 --- a/lemon/bits/graph_adaptor_extender.h	Tue Dec 20 17:36:41 2011 +0100
     2.2 +++ b/lemon/bits/graph_adaptor_extender.h	Tue Dec 20 17:38:19 2011 +0100
     2.3 @@ -181,6 +181,8 @@
     2.4      typedef _Graph Graph;
     2.5      typedef GraphAdaptorExtender Adaptor;
     2.6  
     2.7 +    typedef True UndirectedTag;
     2.8 +
     2.9      typedef typename Parent::Node Node;
    2.10      typedef typename Parent::Arc Arc;
    2.11      typedef typename Parent::Edge Edge;