I'm not entirely sure where this bug lies really. What happens is that the following: [x] { background: red; color:yellow; } ...makes the whole viewport yellow on red, when it should only make elements with an "x" attribute specified those colours. The error may be either with the error handling code (if the selector is not recognised, then the entire rule should be skipped, see CSS1 spec) or with the attribute selector (see CSS2 spec).

Actually, this was working as expected. It just wans't finished. Attribute selectors without an explicit tag are treated as *[x] selectors. Since the attribute selector parst wasn't done, the rule worked like a '*' rule. This should work per spec now.