Hmm ok it's not showing up anymore.. it could of been a cache problem.. but the fact that the source showed that when it wasn't displaying like so is abit weird.
I'm thinking it could of been rendered incorectly since it was in Firefox..
It's a known bug, it has to do with the refill/redraw in firefox and seems to only be limited to that browser as I haven't seen it show it's head elsewhere.