I modified the example, now the bug also appears with Firefox, only IE 6 is doing fine.

I limited the width of the dl element, this screws FF up.

I fixed the Opera bug - however, the other bug is far more complicated and probably not fixable anytime soon. The issue is that since the element is hidden (display: none) I have to break it out of body in order to avoid any flashes of content, when I determine the "true" height/width. Unfortunately, since browsers don't feel like giving the correct height/width for display:none content, this isn't going to be resolved, unfortunately.

See, the quick fix is just to not change the position to 'absolute' - but the problem is that any content beneath it will be shoved, temporarily, out of position - which is highly undesirable. So, long story short, if you want to slideDown something with a width:auto *within* something with a fixed width container, you'll need to limit the width in some way using CSS.