public void Remove()
        {
            ClaimTypeElement elem = collection ["test2"];

            collection.Remove(elem);
            Assert.AreEqual(-1, collection.IndexOf(elem), "#01");
            collection.Add(elem);
            Assert.AreEqual(1, collection.IndexOf(elem), "#02");
            collection.RemoveAt(1);
            Assert.AreEqual(-1, collection.IndexOf(elem), "#03");
            collection.Add(elem);
            Assert.AreEqual(1, collection.IndexOf(elem), "#04");
            collection.RemoveAt("test2");
            Assert.AreEqual(-1, collection.IndexOf(elem), "#05");
        }