TypeDescription td = getTypeDescriptionFromTableTreeItem(parent);
AllowedValue av = getAllowedValueFromTableTreeItem(item);
AllowedValue localAv = getLocalAllowedValue(td, av); // must use unmodified value of "av"
AddAllowedValueDialog dialog = new AddAllowedValueDialog(this, av);
if (dialog.open() == Window.CANCEL)
return;
allowedValueUpdate(av, dialog);
allowedValueUpdate(localAv, dialog);
if (!valueChanged)