First of all, Firefox appears to be fine without the extra "folksonomiesHeight" elements. If they're only needed for IE, at least wrap them in conditional comme

First of all, Firefox appears to be fine without the extra "folksonomiesHeight" elements. If they're only needed for IE, at least wrap them in conditional comments. Secondly, div.folksonomies and div.expandButton can both work without position: absolute if you replace the rules for expandButton with these: height: 25px; margin-top: -25px; text-align: right; Pixel units aren't as bad as they used to be, modern browsers can scale the page regardless of what units you use. Replace font-size: 12pt with font-size: 16px to ensure the correct height. As a general tip, look at the conditional comments used for the HTML tag in HTML5 boilerplate (html5boilerplate.com), you can use that to specify workaround rules for IE < 9 (and you could add an IE 9 class yourself). For IE 6/7 you can use Javascript expressions to calculate correct values.