Leaflet/Leaflet — pull request #1745 by jec006 (2013-06-07 17:00:16+00:00)
Title: Properly calculate the y position of the element when parent is positioned relatively

An attempt to deal with https://github.com/Leaflet/Leaflet/issues/1744 - this adds in calculation for the top offset when the item is positioned relative. This fixes an issue with mouse events not getting the correct lat/lng when a parent of the map had a vertical offset.