I have made a fiddle for reference: http://jsfiddle.net/kLFn9/
The overflow:hidden in question is highlighted.
overflow:hidden
Basically, i\'m using :hover:af
:hover:af
I'm not sure what your trying to get at, but I recreated a tooltip framework for you to view. It's basically smoke and mirrors where I call :hover and the .class associated with it.
http://jsfiddle.net/WE8Dw/
Hope this helps.