Last night I landed support for :-moz-any() selector grouping. This allows providing alternatives between combinators, rather than having to repeat the entire selector for once piece that's different. For example, it allowed replacing this rule in our user-agent style sheet: /* 3 deep (or more) unordered lists use a square */ ol ol ul, ol ul ul, ol menu ul, ol dir ul, ol ol menu, ol ul menu, ol me