twitter/bootstrap — pull request #3272 by coreyti (2012-04-27 22:32:38+00:00)
Title: Add "sibling" placement option

prefixing placement with "sibling" will insert the tooltip *before* the source element, and position it based on the source element's position relative to its offset parent.

this change allows for tooltips that will remain properly positioned on window resize & content change, without inserting the tooltip "in" the element, which would be invalid for source elements, for example.

a closed issue that this change should resolve: https://github.com/twitter/bootstrap/issues/3067