Strictly speaking, yes, -margins- in Stata 12 has a bug, if you
think we should be able to revert to the Stata 11 -margins- at will
just by using version control. However, I would prefer to fix my
code instead of complaining, as -margins- is such a wonderful tool.
I'll complain on your behalf though. ;-) If this is indeed a bug in
margins, I hope it will be fixed. We can't count on always having
people like Roger who will quickly rewrite their programs. Plus,
version control is one of the very nice features of Stata so we want
to keep it working right unless there is some compelling reason not to.