public override sealed void Save(ConfigNode parent)
        {
            ConfigNode node = new ConfigNode("poderosa-container");

            foreach (ConfigElementAttribute attr in _configAttributes)
            {
                attr.ExportTo(this, node);
            }
            node["framePosition"] = String.Format("{0},{1},{2},{3}", _framePosition.X, _framePosition.Y, _framePosition.Width, _framePosition.Height);
            parent.AddChild(node);

            _commands.Save(parent);

            base.Save(parent);
        }