So I ran into this problem when trying to make a map, my elevation tab in layers, if I click on it I'll get a Elevation brush box with greyed out sliders of Strength, Size, Maximum, Minimum and the box that should show brushes is totally blank, I'll try get a screenshot in here too.
Thanks,
Omit
Edit : It's a fully updates steam version of the original SupCom, and yes I did try with CD install.. :/