XForms/Xamarin-Forms-Labs — pull request #231 by WillooWisp (2014-08-20 18:55:20+00:00)
Title: Implementation changed (reworked) to function for iOS and Android as well

... and not only WP8, since the Appearing and Disappearing events where not received for the application's Main Page after OnPropertyChanging for CurrentPage property as with all other pages being navigated to/from.