Running into an issue (mis?)using the techniques on this page. Demonstrated here: http://jsfiddle.net/ezX3P/1/
If you click the "Update Window" and "Back" buttons multiple times, it fires a single "alert" like it should, but as soon as you click the "Update Id" on the second screen, it starts duplicating the event bindings (as far as I can tell) so that if you then click on "Back" or "Update Window", they fire twice. It appears to double every time the "Update Id" button is clicked.