Menu menu = super.createContextMenu(colIndex);
if (menu != null && enableGroupingMenu && cm.isGroupable(colIndex)) {
MenuItem groupBy = new MenuItem(GXT.MESSAGES.groupingView_groupByText());
groupBy.setIconStyle("x-group-by-icon");
groupBy.addSelectionListener(new SelectionListener<MenuEvent>() {
@Override
public void componentSelected(MenuEvent ce) {
onGroupByClick(ce, colIndex);
}