I\'m not sure whether this bug applies to Firefox only or also to WebKit-based browsers, but it\'s really, really annoying.
I\'ve got a template/framework for my CMS in
Since I'm dealing with the same annoying issue, I'll go ahead and chime in here to say that this is definitely a shitty feature (if indeed it should be referred to as a feature). To have a box shadow cause a scroll bar is useless, though I'd be happy to eat my words if someone could give me a really good reason that it should be like that.
I think the answer here is just rendering the page a little different and letting firefox users miss out on the box shadow. Easy enough if you just don't declare -moz-box-shadow
.