public async Task Refresh()
        {
            FontGroups.Clear();
            FontGroupOptions.Clear();
            await App.Repository.RefreshAsync();

            AddFontsFromRepository();
        }
 public void AddFontsFromRepository()
 {
     foreach (var g in App.Repository.GetFontGroups())
     {
         FontGroups.Add(g);
     }
     foreach (var g in App.Repository.GetFontGroupOptions())
     {
         FontGroupOptions.Add(g);
     }
 }