twitter/bootstrap — pull request #7522 by flegall (2013-04-09 19:49:53+00:00)
Title: Fixes #7521

https://github.com/twitter/bootstrap/issues/7521

This makes sure the IE8 error is caught when trying to focus () on an invisible element.
When the element is invisible, I don't think it should be made visible for focusing.

I've only modified the source JS files, not the generated ones.