When working on maps and mapsets created on the mainframe, you should bear the following in mind:
Maps and mapsets created on the mainframe may use the POS=number convention (as opposed to POS=(row,col)). The BMS macros are generated always in the POS=(row,col) format.
Overlapping fields are supported on downloaded maps but cannot be created with the painter. You can move an overlapping field by dragging it, but once it has been fixed on another part of the map it cannot be returned to its original overlapping position.
BMS files that contain conditional Assembler statements or COPY statements cannot be directly read.