private void NewProduct_Click(object sender, RoutedEventArgs e)
        {
            EditProductWindow _new = new EditProductWindow(null);

            _new.ShowDialog();
            updateProducts();
        }
        private void Products_MouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            Product           selected = (Product)Products.SelectedItem;
            EditProductWindow _new     = new EditProductWindow(selected);

            _new.ShowDialog();
            updateProducts();
        }