I posted a ticket but it was rejected as a sapn. So I wrote it my blog and linked it. Trac Error Submission rejected as potential spam (Akismet says content is spam) http://bugs.jquery.com/newticket http://bugs.jquery.com/ticket/9776 - ".\" is a completely valid CSS selector. CSS Validator Result: http://jigsaw.w3.org/css-validator/validator?text=.tab%5C%3Cimg%5C%3E+%7B%0D%0A++++background-color+%