public void menuUpdate(ActionEvent event)
{
ColumnData data = ColumnData.getInstance();
Object src = event.getSource();
JCheckBoxMenuItem item = (JCheckBoxMenuItem) src;
PopupMenu menu = (PopupMenu) item.getParent();
String key = event.getActionCommand();
int selectedCount = 0;
for (JMenuItem x : menu)
{
selectedCount += x.isSelected() ? 1 : 0;