I've found what I think could be a bug in IE, and my (reasonably)
extensive searching has not thrown up anybody else talking about it. I
could, however, be looking in all the wrong places...

Essentially if an alpha filter is used to create varying levels of
transparency on an absolutely position div, the text becomes blurry.
It doesn't happen in Mozilla Firefox. Here is a test case:
http://michaeldent.com/test/.

My question is:
a) Is this a known bug, or supposed to happen?
b) Is there a workaround?