Crystal Office Systems

I'm a very happy long time Maple user

Now, I've just bought another copy for my wife. Could somebody explain exactly how the multi user access works? I am allowed to open the file twice (via File, Open) but what happens if one of us try to make changes?

Only one user can access .mpl file in full-acces mode (the first one who open the file). All other user will be able to view and naviage through the database, but all their changes will be discarded.