It's still working for me in Firefox, IE, Google Chrome and Safari in Windows, and Firefox, Google Chrome, Epiphany and Konqueror in Linux - and I've tried it on three different computers. How bizarre. I honestly have no idea what to tell you.
Truthfully, though, I don't like the feature because, as we've mentioned before, it can miss posts. Why? Who knows? Hopefully that will be something that will be fixed in SMF 2.0. (Speaking of which, the third release candidate of 2.0 came out back in March, so the official release may not be that far off - and we'll be upgrading to it once it is released...)