mozilla/shumway — pull request #1743 by tschneidereit (2014-09-25 11:49:59+00:00)
Title: Bug 1071422 - Change all of Event's and important subclasses' methods to native implementations

This not only fixes the issue at hand, it also improves speed of mouse handling by speeding up cloning. And I guess it gives us slight startup speed improvements, too.