twitter/bootstrap — pull request #4161 by senfo (2012-07-23 21:55:26+00:00)
Title: Remove position style from .collapse class

The "position: relative;" style in the .collapse class was causing issues for me. It didn't seem like it was necessary for the style to exist so I removed it. I've tested and haven't noticed anything that I broke, but I'm not 100% confident.

Imagine a multi-column page in which the far left column contains "draggable" content (something you can drag from the far left column into another column). Because of the way "overflow: auto;" works, content dragged from the left column will disappear at the boundaries of the column. By removing the "position: relative" style, we are able to overcome this issue while maintaining proper collapsing functionality.