children, siblings, etc. don't work with "tag.class" selectors

[andrewchilds]

Using "tag.class" selectors on methods like children, siblings, etc. appear to short-circuit on matches of "tag".

Demo using jQuip:
http://jsfiddle.net/ZBTVJ/1/

Demo using jQuery:
http://jsfiddle.net/hH4yF/1/