XUL box layout

I ran across an old posting from dbaron about how CSS’s 2nd generation still can’t do simple box layout needed for UI, which means that the web is full of hacky table tags. XUL box layout, which appears to be headed for standardization in the CSS working group, is a known solution that should be available to web app builders. Mozilla supports XUL, and Safari has XUL box layout support via CSS extensions.