protected MainMenuLauncher()
 {
     if (Current == null)
     {
         this.Hide();
         Current = this;
         Nav.HardwareBack.InsertHandler(HardwareBackHandler, 0);
     }
 }
        static MainMenuLauncher()
        {
            Nav.FullRefreshed.Handle(async() =>
            {
                await(Overlay?.RemoveSelf()).OrCompleted();
                Overlay = new Overlay();

                await(Menu?.RemoveSelf()).OrCompleted();
                Menu = null;

                await(Current?.RemoveSelf()).OrCompleted();
                Current = null;
            });
        }