private void ManageAllCards_Click(object sender, RoutedEventArgs e)
        {
            var collection = new TrulyObservableCollection <CardInCollection>(SetsInfo.SelectMany(si => si.SetCards).ToList());

            OpenCollectionForEditing(collection);
        }
 private void ManageAllCards_Click(object sender, RoutedEventArgs e)
 {
     OpenCollectionForEditing(SetsInfo.SelectMany(si => si.SetCards));
 }