public void Save(XmlWriter writer)
        {
            writer.Write(WindowStateKey, (int)WindowState);
            writer.Write(HeightKey, Height);
            writer.Write(WidthKey, Width);
            writer.Write(LeftKey, Left);
            writer.Write(TopKey, Top);

            writer.Write(LicensePathKey, LicensePath);
            var indexesWriter = writer.CreateChildWriter(IndexesKey);

            foreach (var index in Indexes)
            {
                var indexWriter = indexesWriter.CreateChildWriter(IndexKey);
                index.Save(indexWriter);
            }
        }