(Firefox 7, Linux)
Otherwise you get a nice off-white box in the middle of the screen, and not much else.
Got it working in Firefox, or at least I think I did. This is kinda awful, and I do mean that with respect. I'd much rather mouse over the labels on the right and have the message pop up instantly. The delay and amount I have to scroll makes this awkward. I thought it was broken still until I gave up and the message popped in.