Weird. I'm also using firefox, version 3.5.7, and am experiencing the total opposite. Forum collapse works, last post does not work at all. I don't even get the visual indicator on a post to say that it's new.
Heh, more weird. I have the same version of Firefox, and forum collapse works for me, as well as the last post button. And the threads are bolded if there are any new posts I have not seen in them.
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