layout.addComponent(new Label("some row"), 0, 0);
Button newRowButton = new Button("Insert Row");
newRowButton.addListener(new Button.ClickListener() {
@Override
public void buttonClick(ClickEvent event) {
layout.insertRow(1);
layout.addComponent(new Label("some new row"), 0, 1);
}
});
layout.addComponent(newRowButton, 0, 1);
addComponent(layout);