/// <summary>
            /// Gets the item at the specified index in the collection.
            /// </summary>
            /// <param name="index"></param>
            /// <returns></returns>
            public GeckoStyleSheet this[int index]
            {
                get
                {
                    if (index < 0 || index >= Count)
                    {
                        throw new ArgumentOutOfRangeException("index");
                    }

                    return(GeckoStyleSheet.Create((nsIDOMCSSStyleSheet)List.Item(index)));
                }
            }