RowDetailsCreator.java

...
...
  Button button = new Button();
  button.setType(..);
...
  Element th1 = DOM.createTH();
  th1.appendChild(button.getElement());
  
  // NOT WORKING: add click event to Button
  button.addClickHandler(event -> {
     logger.info("OnBrowserEvent: OK");
  });

  // NOT WORKING: add click event to Button
  Element buttonElement = button.getElement();
  Event.sinkEvents(buttonElement, Event.ONCLICK);
  Event.setEventListener(buttonElement, event -> {
     logger.info("OnBrowserEvent: OK");
     if (Event.ONCLICK == event.getTypeInt()) {
	logger.info("OnBrowserEvent: OK");
     }
  });