twitter/bootstrap — pull request #2423 by pelme (2012-03-06 13:27:20+00:00)
Title: Collapse overflow fix

Currently, ```.collapse.in``` specifies ```overflow: hidden```, probably to make the animations behave correctly.

This causes problems when using drop-downs or other dynamic content that overflows the collapse area.

This can be seen in this jsfiddle:
http://jsfiddle.net/rdXfZ/1/

The commit simply uses overflow: visible for .collapse.in, and patches the show/hide in collapse() to properly set overflow.