// Grid
GridLayer gridLayer = new GridLayer(compFreeze, columnHeaderLayer,
rowHeaderLayer, cornerLayer, false);
CompositeLayer compositeGridLayer = new CompositeLayer(1, 2);
final GroupByHeaderLayer groupByHeaderLayer = new GroupByHeaderLayer(
groupByModel, gridLayer, columnHeaderDataProvider);
compositeGridLayer.setChildLayer(GroupByHeaderLayer.GROUP_BY_REGION,
groupByHeaderLayer, 0, 0);
compositeGridLayer.setChildLayer("Grid", gridLayer, 0, 1);
NatTable natTable = new NatTable(comp, compositeGridLayer, false);
natTable.addConfiguration(new DefaultNatTableStyleConfiguration());
natTable.addConfiguration(new GroupByHeaderMenuConfiguration(natTable,
groupByHeaderLayer));