twitter/bootstrap — pull request #6612 by gyoshev (2013-01-17 10:01:45+00:00)
Title: Use floats instead of font-size:0 hack to accommodate nested content

This allows for nested content such as validation tooltips (both Bootstrap and third-party). Closes #6236. See further details in [my comment on the issue](https://github.com/twitter/bootstrap/issues/6236#issuecomment-12361151).