I have an absolutely positioned `div` containing several children, one of which is a relatively positioned `div`. When I use a `percentage-based width` on the child `div`, it collapses to `0 width` on IE7, but not on Firefox or Safari. If I use `pixel width`, it works. If the parent is relatively positioned, the percentage width on the child works. 1. Is there something I'm missing here? 2. Is there an easy fix for this besides the `pixel-based width` on the child? 3. Is there an area of the CSS specification that covers this?