code: private void addEmptyLabel()
    {
      if (emptyLabel == null)
      {
        emptyLabel = new Label("none");
      }
  
      if (corpusAnnotationTable != null)
      {
        layout.removeComponent(corpusAnnotationTable);
      }
  
      layout.addComponent(emptyLabel);
  
      // this has only an effect after adding the component to a parent. Bug by vaadin?
      emptyLabel.setSizeUndefined();
  
      layout.setComponentAlignment(emptyLabel, Alignment.MIDDLE_CENTER);
      layout.setExpandRatio(emptyLabel, 1.0f);
    }
docs: Places a label in the middle center of the corpus browser panel.