public void AddCommentInsertsLast()
        {
            var model = new Sequence();

            model.AddComment(new Comment {
                Text = "First", MarkIn = 0
            });
            model.AddComment(new Comment {
                Text = "Second", MarkIn = 1
            });

            Assert.AreEqual("First", model.CommentElements[0].Text);
            Assert.AreEqual("Second", model.CommentElements[1].Text);
        }