Other suggestions for improvement I have are changeing the colour of an unknown section so that it is different to a wall section. Both are black so its not obvious when you come to a wall, it might just be the end of your vision.
Also a larger scale would be nice as an option. If I were using it from a laptop it might be difficult for people to see the detail from the other end of the table.
Also, is it possible to save the map as a graphic file (bmp/jpg/gif) for inclusion in a scenario write-up.
All in all though, so far so good - keep up the good work!