In my project, I'm using several different graph objects that are declared in different namespaces. All of these graphs use default internal color maps. Suppose I declare a graph in namespace A. In another namespace, say namespace B, I attempt to invoke a DFS using the named parameter version of the call specifying only the visitor and defaulting the rest of the parameters. Specifically, I do not specify the color map in the named parameter list. What I expected was that the DFS would find, and use the default internal color map of the graph declared in namespace A. However, it appears that it does not and allocates a temporary color map (I assume the compiler searches namespace B, not A). Subsequently when DFS attempts to initialize the color map to white, a fault occurs at runtime (I haven't had time to get into the guts of DFS and figure out exactly why this bombs yet). I've worked around this by using the standard (sans named parameters) version of the DFS call (explicitly passing in a reference to the internal color map). This seeming interaction between the named parameter mechanism and namespaces is pretty subtle - if not for the runtime fault, I would likely have never noticed that the internal property map wasn't being used during the search. Has anyone else seen this? - Chris