Unstyled non-empty inline elements with no content give rise to a line box of positive height in IE 8 beta 1, whereas the CSS 2.1 Candidate Recommendation says that “empty”1 inline elements “generate empty inline boxes” and also says that line boxes that “contain no text, no preserved white space, no inline elements with non-zero margins, padding, or borders, and no other in-flow content (such as images, inline blocks or inline tables), and don’t end with a line feed must be treated as zero-height line boxes”.
This bug has serious consequences for markup of the form
<div><a><img src="foo.html" alt=""></a></div>
when the image is then absolutely positioned: the a element gives rise to an empty line box of positive height inside the div in IE 8 beta 1, which causes the div to have positive height, thus breaking any layout which relies on that div having zero height. It would be highly undesirable for this bug to go unfixed, as is breaks the universally-assumed ‘insignificance property’ of the a element which allows inline boxes to be linked or unlinked without creating a change in the layout.