void HandleSetDateRange (object sender, EventArgs args)
{
var date_range_dialog = new DateRangeDialog (query.Range, main_window);
if ((ResponseType)date_range_dialog.Run () == ResponseType.Ok)
query.Range = date_range_dialog.Range;
date_range_dialog.Destroy ();
//update the TimeLine
if (group_selector.Adaptor is TimeAdaptor && query.Range != null)
group_selector.SetLimitsToDates (query.Range.Start, query.Range.End);
}