Hi Colin
Just open another map (Map...Open/Save and if you want, chose the default map or any other one).
Then choose Window...Tile and choose Vertical or Horizontal.
You treat each map individually, with different colours, satellite overlays, etc. Just click on the map you want to change before you change it.
I'm not sure how well this worked in V2 - I'm using the closed beta version and it works a treat!
Rod