Like many people, including the jQuery UI official, they use a method of multiple class to achieve something, I get annoyed easy and wish to have a shortcut for this… the answer is amazingly simple as you will all slap your foreheads once you realise it’s simplicity.

Have you ever done the following?

Well here is the same example but without having to prepend the icon (first class).

style.css

OR simply use the white space instead of the hyphen.

As you can see form this jsFiddle That you can use
.icon, .icon.setting, .setting{ /* what ever*/} and the thing wont be affected… This method is cross browser as it has been since CSS2 (will except really old browsers as explain here on this page http://reference.sitepoint.com/css/attributeselector#compatibilitysection.