title: Background Image not showing where negative top-margin set in Firefox
body: <p>I have a scrolling image section (the images are background images not ing tags) that uses top-margin: -28px; to move it below a portion of the header on a site I'm making. It's displaying perfectly on Safari, Chrome etc but on Firefox the top 28px of the image are not displaying.</p>
  
  <p>Any ideas why? I have no idea and it's driving me nuts.</p>
  
  <p>The site is here <a href="http://www.chelt.org.uk" rel="nofollow">http://www.chelt.org.uk</a></p>