protected override void OnClick() {
     if (_isOpen)
         return;
     _isOpen = true;
     _dlg = new CoordSysDialog();
     _dlg.Closing += bld_Closing;
     _dlg.Owner = FrameworkApplication.Current.MainWindow;
     _dlg.Show();
 }
        public override bool SelectSpatialReference()
        {
            if (_isOpen)
                return false;

            _isOpen = true;
            _dlg = new CoordSysDialog();
            _dlg.Closing += bld_Closing;
            _dlg.Show();

            return false;
        }