If you’ve recently started using IE8, you might notice the default MOSS/SharePoint master pages are not rendering properly.
You can fix this quickly by adding this to your master page to tell IE8 how to render:
1 <span class="kwrd"><</span><span class="html">meta</span> <span class="attr">http-equiv</span><span class="kwrd">="X-UA-Compatible"</span> <span class="attr">content</span><span class="kwrd">="IE=7"</span> <span class="kwrd">/></span>
Of course the better solution is to create a master page that is properly XHTML compliant.