I am also running Win7 64bit. For me the drop down Menu was working fine with five state maps that I had downloaded and installed from this site THEN the drop down quit working after about 5 days. I also tried various uninstall/re-install/restart combos, and system restore. After reding this thread this is what I did: I uninstalled everything except MapSource and also deleted the map downloads that I had saved. Then I downloaded and installed MY Trails followed by some state maps. Now the drop down WORKS!
Thanks for the help!
