Comment 46 for bug 31746

Yeh, I think the important ones are:
   It should be documented how to do this - it's not that uncommon a request
  The interaction with -a and -P is just wrong, common options shouldn't 'sometimes work'.
  It seems to me that -P should just work irrespective of -a (possibly by implying -a)
    just because it's not useful without it.

Dave
P.S. Where is the firefox manpage?