I've just skimmed through this.. You should maybe be a bit more loose in your questioning, you appear to be assuming that everyone that programs Perl uses Emacs, and everyone programming Java uses Eclipse, clearly this is not the case.. To allow everyone to answer, and not with "But don't use Emacs, use Editor XXX", you should maybe invite comments from users of other editors as well. (I also suspect you'll get a lot of comments about Emacs not being the most advanced Perl IDE too.. but thats your choice I guess)

First note though: Have you looked at the Perl plugin for Eclipse? I think its http://e-p-i-c.sourceforge.net - I'm not sure it does simultaneous docs though..

In Emacs, anyway, I use the wonderful "split window" command (ctrl-x 2), and open the manpage of whatever I need in the second window (ctrl-x o M-x man Set::Object), or just have it open in another terminal.. Since I don't use my editor windows full screen, that works fine too.

C.