It only works for messages that you haven't read...if you read it right away, or something, then it won't popup. You'll have to refresh also, on some page other than the PM page, I believe.
Yep, that stuff shouldn't have been an issue...I've always gotten the popup on other vB sites, so I was just wondering whether this feature was actually working or if it was some weird thing on my end (for example Netscape 6 is doing some really screwy things on my system, even though I've seen it work flawlessly on other people's systems...anyway, it's having some weird effects and I thought that might be one of them.)