My edge properties struct has a bool "on" member. At times I may want to change whether an edge is on or not, and then I want to generate filtered_graphs that contain only the on or off edges for use with BGL algorithms. However, it doesn't seem to be working. If I do: func(Graph &G) { filtered_graph<Graph> F1(G,OnEdges(G)); // iterate over the edges of F1 and print them out // Now iterate over the edges of G and turn some of them off, printing out which ones filtered_graph<Graph> F2(G,OnEdges(G)); // iterator over the edges of F2 and print them out } then I end up getting the exact same set of edges from F1 and F2! F2 even shows the edges I turned off in between. What exactly is filtered_graph doing that this is possible? Related question: If I have a filtered_graph of on edges, and I turn one of them off *through* it, what happens?