I'm curious if you figured out how to disable the selection color?
The only thing I could think of is to convert the map to a background image, which will "lock it."
See attched. To get this, I
1) removed the cities from your map
2) exported the map to a JPG, which will later be used as a background image
3) crated a test_lat_long.xls file to determine the lat/long coordinates of the map.
4) added the saved map image as a background image with these coordinates (Map > Background Images > Hoja.xls > Add)
5) crated a new sheet with City level of detail and lat/long(generated) fields, but disabled the background map (Map > Background map > none) to show the background image.
This isn't very convenient, unless it's a single map you're working with.
Allan Walker does a lot of work with maps and may have some ideas.
I see another problem here:
This won't answer your problem Stuardo, but the fill isn't "filling" the data area!
Maybe use Tiger US States as a shapefile background image, and use city as the lowest level of detail, unless you have data at the state level as a roll-up.