var orderedModel = unorderedModel
			.SelectManyRecursive(x => x.Children.Select(y => {
				if (x.RootSortOrder == null) x.RootSortOrder = x.SortOrder;
				y.RootSortOrder = x.RootSortOrder;
				return y;
			}))
			.OrderBy(x => x.RootSortOrder)
			.ThenBy(y => y.Parent == null ? null : y.Parent.Title)
			.ThenBy(y => y.Title)
			.ToList();