private void DoRefresh()
{
var list = NodesTable = new ObservableCollection <NodeDbTableToExcel>();
RefreshHelper.RefreshTables(eventAgg, root, ref list);
NodesTable = list;
// slow?? :-)
SetDescShown(AreDescsShown);
//third tree view... (Tables-Columns -> Excels -> Sheets)
DoRefreshColumns();
}