void SaveConfig()
        {
            string filename = Utils.GetFile();

            if (filename.Length < 1)
            {
                return;
            }
            PersistSettings.Save(ColumnCollection.Columns, filename);
        }
        void LoadPersistedConfig()
        {
            string filename = Utils.GetFile();

            if (filename == null)
            {
                return;
            }

            object loadedobject = PersistSettings.Load(filename);

            if (loadedobject != null)
            {
                ColumnCollection.Columns = (ObservableCollection <ISessionColumn>)loadedobject;
            }
        }