ajaxorg/ace — pull request #539 by singjie (2011-11-29 13:41:32+00:00)
Title: Fix contextMenu when accessing editor requires scrolling

When editor is not at the top of the page (requires scrolling), textarea
right-click context menu will fail to appear.

Use clientX and clientY which returns the relative coordinates instead
of pageX and pageY.

Image attached for better illustration - notice the browser vertical scroll bar:
Without scrolling (works fine): http://i40.tinypic.com/1icsq8.png
With scrolling (breaks - shown wrong context menu): http://i42.tinypic.com/14cfyi8.png