rocknbil - 4:45 pm on Mar 30, 2011 (gmt 0)
Did you try it on a non-empty element? It doesn't have to be an anchor.
<a href="#anchor">to anchor</a>
<h2 id="anchor">Topic three</h2>
I just tested it using ID's but don't have 4.0, maybe it's specific to 4.0 - did you validate all documents?