WinPhone & Win 8.1: Crash on Navigation.PopModalAsync() if the page contains and Editor

I have a xaml page “Details_View” showed with ContentPage.Navigation.PushAsync(Details_View) with an Editor inside.

If I call Navigation.PopModalAsync() the app crashes (happens only on WinPhone and Win8.1. With Andro & iOS is OK) with the following exception:

System.NullReferenceException: Object reference not set to an instance of an object.
at Xamarin.Forms.Platform.WinRT.EditorRenderer.OnLostFocus(Object sender, RoutedEventArgs e)

If I remove the Editor the app don’t crash any more.

Any idea?

May be a good idea try to override Xamarin.Forms.Platform.WinRT.EditorRenderer.OnLostFocus()?