buttonLayout.setMembersMargin(5);
buttonLayout.setHeight(25);
// Create a button to show the "roads" objects into a FeatureGrid:
IButton button1a = new IButton("Show roads");
button1a.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
VectorLayer layer = (VectorLayer) getMap().getMapModel().getLayer("roadsLayer");
table.setLayer(layer);
layer.getFeatureStore().getFeatures(GeomajasConstant.FEATURE_INCLUDE_ALL, new LazyLoadCallback() {