2 column layout that doesn't require JS to align the sidebar to the top, or knowledge of height of elements prior to sidebar. Best solution. http://jsfiddle.net/patrickmarabeas/qgQ4X/ Uses inline-block and vertical align top instead of float right for the sidebar.
Webkit doesn't play well with transitions which include a change in float value. Float value needs to be changed, then examined, before the class which changed the elements value which has the transition coupled to it is added.