Thanks for the suggestions - setting the color to transparent may be the way to go.
I understand about the files and that would work if I could have multiple files open at once, but I can't seem to do that. I may be trying to get functionality that doesn't exist from Mapsource that I'm used to in my other mapping & GIS programs! I typically use Delorme XMap, a couple of ESRI products (Arcview, etc), AllTopov7, etc. In all of those you can choose what to display on the map without actually removing items from the workspace.