[Highlight column on click - Devexpress GridControl]

Form.cs

private void gvSourceData_MouseDown(object sender, MouseEventArgs e) {
  var gridView = sender as GridView;
  GridHitInfo hi = hi = gridView.CalcHitInfo(gridControl.PointToClient(MousePosition));

  if (!hi.InRowCell && !hi.InColumn) {
    ((DXMouseEventArgs)e).Handled = true;
    return;
  }

  gridView.ClearSelection();
  for (var i = 0; i < gridView.RowCount; i++) {
    gridView.SelectCell(i, hi.Column);
  }

  ((DXMouseEventArgs)e).Handled = true;
}