No doubt this is another typical question that the lousy Help function SW couldnt answer.

Anyway, I want to split the BOM into two, nothing fancy, 2 parts next to each other. Thats it. It seems to be a lottery as to when this function appears in the right click menu (the SPLIT function)

Can anyone explain why this is?

Its probably one of those "oh you didnt know to do this?" answers, that always seem to "present itself" only when you get on a forum and ask half a million people. Never an intuitive help function within the software itself. I guess you get what you pay for.