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
I don't know your site's layout, but on mine I only ever want vertical scrolling, and not horizontal. That serves as part the basis as to why the box-shadow causing horizontal scrolling is undesirable for me, since my site's CSS in now way is build for layouts sprawling horizontally beyond the viewport.
I was able to fix it in Firefox 3.6 (that's all I tested) and tested it cross-browser to Google Chrome 8.0.552.327 and IE 8 with the following CSS rule on my body element:
body{
overflow-x: hidden;
}