Wedge

Hmm, yes..?
Originally, it was done this way yes, but I never had any reason to do it otherwise... It's a separator between posts, if you want to style something below posts, you can always do an :after or something on the #forumposts container..?

Then it's buggy.

Say a thread is three pages long. The separator shows after the last post on the first two pages, but not on the third.

Hmmmmmmmmm....
But perhaps then, perhaps it's something to do with the fact that infinite scrolling will need to add that separator anyway..? :P

Nah, who am I kidding... Yeah, it's a bug, there shouldn't be a separator on the last post of every page, and I shan't blame infinite scrolling for that. I somehow remember 'fixing' separators years ago, long before I thought of infinite scrolling, actually...
Okay, so I'm seeing that I'm basing my calculations off id_last_msg, which is a bit silly.

Oh, bugger, I had a quick look, and couldn't find a variable that determines the position in the page... Something based off $counter, or whatever.
Maybe I should just leave all separators in, and count on themers to just NOT style the last one too differently, by targeting it through .sep:last-child, or something...?

At least it'll be consistent that way.