protected override async void OnAppearing()
 {
     base.OnAppearing();
     PanGesture.PanUpdated += OnPaned;
     TapGesture.Tapped     += GridTapped;
     await Model.Load();
 }
 protected override async void OnAppearing()
 {
     base.OnAppearing();
     MessagingCenter.Subscribe <ZonesPlanViewModel>(this, "Rebuild", Rebuild);
     MessagingCenter.Subscribe <ZonesPlanViewModel>(this, "Reshape", Reshape);
     MessagingCenter.Subscribe <ZonesPlanViewModel>(this, "BringToFront", BringToFront);
     PanGesture.PanUpdated += OnPaned;
     TapGesture.Tapped     += GridTapped;
     await Model.Load();
 }