ListView is not scrolling with grouping

I simply changed my ListView to use grouping, but now I can't use ScrollTo anymore.

I have create a simple app, so you can see the problem.

The XAML-page looks like (I am not using XAML in my app at the moment, but I will in an upcoming version).

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
   xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
   xmlns:local="clr-namespace:ScrollListExample"
   x:Class="ScrollListExample.ProjectPage">

   <Grid>
      <Grid.RowDefinitions>
         <RowDefinition Height="Auto" />
         <RowDefinition Height="*" />
      </Grid.RowDefinitions>

      <ListView x:Name="ProjectsListView" HasUnevenRows="True" IsGroupingEnabled="True" ItemsSource="{Binding Projects}">
         <ListView.GroupHeaderTemplate>
            <DataTemplate>
               <ViewCell>
                  <Label Text="{Binding Path=Key}" />
               </ViewCell>
            </DataTemplate>
         </ListView.GroupHeaderTemplate>
         <ListView.ItemTemplate>
            <DataTemplate>
               <ViewCell>
                  <Grid>
                     <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="Auto" />
                     </Grid.ColumnDefinitions>
                     <Label Grid.Column="0" Grid.Row="0" LineBreakMode="TailTruncation" Text="{Binding Path=ProjectName}" />
                     <Label Grid.Column="0" Grid.Row="1" Text="{Binding Path=ProjectReference, StringFormat='Sag: {0}'}" />
                     <Label Grid.Column="0" Grid.Row="2" Text="{Binding Path=CustomerName}" />
                     <Label Grid.Column="0" Grid.Row="3" Text="{Binding Path=FullAddress}" />
                     <Label Grid.Column="1" Grid.Row="0" Text="{Binding Path=StartTime}" />
                  </Grid>
               </ViewCell>
            </DataTemplate>
         </ListView.ItemTemplate>
      </ListView>
   </Grid>

</ContentPage>

And the code-behind file for the example looks like this

[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class ProjectPage : ContentPage
{
   public ProjectPage()
   {
      InitializeComponent();
      BindingContext = new ProjectsViewModel();
   }

   protected override void OnAppearing()
   {
      base.OnAppearing();

      Acr.UserDialogs.UserDialogs.Instance.ShowLoading();

      var projects = Newtonsoft.Json.JsonConvert.DeserializeObject<IList<ProjectDto>>("[{\"ProjectName\":\"Test sag\",\"ProjectReference\":\"10072\",\"CustomerName\":\"Test firma\",\"FullAddress\":\"Testvej 3\",\"StartDate\":\"2017-02-02T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"aaa\",\"ProjectReference\":\"10077\",\"CustomerName\":\"Test firma\",\"FullAddress\":\"Testvej 12\",\"StartDate\":\"2017-02-08T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10082\",\"CustomerName\":\"Test firma\",\"FullAddress\":\"Testvej 50\",\"StartDate\":\"2017-02-16T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10085\",\"CustomerName\":\"Testvej boligselskab\",\"FullAddress\":\"Testvej 14\",\"StartDate\":\"2017-02-24T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10086\",\"CustomerName\":\"Testing\",\"FullAddress\":\"Testevej 14\",\"StartDate\":\"2017-02-27T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test1\",\"ProjectReference\":\"10087\",\"CustomerName\":\"Plejecenter testlyst\",\"FullAddress\":\"Testlystvej 11\",\"StartDate\":\"2017-02-27T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test2\",\"ProjectReference\":\"10088\",\"CustomerName\":\"Charlie\",\"FullAddress\":\"Testvej 50\",\"StartDate\":\"2017-02-27T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10089\",\"CustomerName\":\"Standard Debitor\",\"FullAddress\":\"[Mangler]\",\"StartDate\":\"2017-03-16T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10090\",\"CustomerName\":\"Standard Debitor\",\"FullAddress\":\"[Mangler]\",\"StartDate\":\"2017-03-16T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10091\",\"CustomerName\":\"Standard Debitor\",\"FullAddress\":\"[Mangler]\",\"StartDate\":\"2017-03-16T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10092\",\"CustomerName\":\"Tester\",\"FullAddress\":\"Testvej 11\",\"StartDate\":\"2017-03-16T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10093\",\"CustomerName\":\"Plejehjemmet test\",\"FullAddress\":\"Testvej 90\",\"StartDate\":\"2017-03-16T00:00:00\",\"StartTime\":\"\"},{\"ProjectName\":\"Test\",\"ProjectReference\":\"10094\",\"CustomerName\":\"Plejehjemmet test\",\"FullAddress\":\"Testvej 90\",\"StartDate\":\"2017-03-16T00:00:00\",\"StartTime\":\"\"}]");

      var viewModel = BindingContext as ProjectsViewModel;
      if (viewModel != null)
         viewModel.OriginalProjects = projects;

      Acr.UserDialogs.UserDialogs.Instance.ShowLoading("Loading");

      Task.Delay(5000).ContinueWith((x) =>
      {
          Device.BeginInvokeOnMainThread(Acr.UserDialogs.UserDialogs.Instance.HideLoading);

         Search();
      });
   }

   private void Search(string inputVal = null)
   {
      var viewModel = BindingContext as ProjectsViewModel;

      if (viewModel != null)
      {
         var projects = viewModel.OriginalProjects.Where(p => !string.IsNullOrEmpty(inputVal) ? p.ProjectName.Contains(inputVal) : true);

         var orderedProjects = projects.OrderBy(p => p.StartDate);

         Device.BeginInvokeOnMainThread(() =>
         {
            foreach (ProjectDto project in orderedProjects)
            {
               var coll = viewModel.Projects.FirstOrDefault(c => c.Key == project.StartDate);

               if (coll == null)
                  viewModel.Projects.Add(coll = new ObservableCollectionWithDateKey { Key = project.StartDate });

               coll.Add(project);
            }

            var group = viewModel.Projects.LastOrDefault();
            if (group != null)
               ProjectsListView.ScrollTo(group.First(), group.Key, ScrollToPosition.Start, false);
         });
      }
   }
}

class ProjectsViewModel : INotifyPropertyChanged
{
   private ObservableCollection<ObservableCollectionWithDateKey> _projects;

   public event PropertyChangedEventHandler PropertyChanged;

   public IEnumerable<ProjectDto> OriginalProjects { get; set; }

   public ObservableCollection<ObservableCollectionWithDateKey> Projects
   {
      get { return _projects; }
      set
      {
         _projects = value;
         PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Projects)));
      }
   }

   public ProjectsViewModel()
   {
      Projects = new ObservableCollection<ObservableCollectionWithDateKey>();
   }
}

public class ProjectDto : INotifyPropertyChanged
{
   public string ProjectName { get; set; }
   public string ProjectReference { get; set; }
   public string CustomerName { get; set; }
   public string FullAddress { get; set; }
   public DateTime StartDate { get; set; }
   public string StartTime { get; set; }

   public event PropertyChangedEventHandler PropertyChanged;
}

class ObservableCollectionWithDateKey : ObservableCollection<ProjectDto>
{
   public DateTime Key { get; set; }
}