title: RightClick CellTable Header
body: <p>I need to make the column headers of my celltable to do something on right click.</p>
  <p>I implemented a header which uses by now a clickabletextcell, but can be anything.</p>
  <p>here is how I declare my celltable so far:</p>
  <pre><code>Header header = new Header(new ClickableTextCell()) {
  
      @Override
      public String getValue() {
          return actual.getCaption();
      }
  };
      
          
  TextColumn&lt;ObjetoDato&gt; columna = new TextColumn&lt;ObjetoDato&gt;() {
      
      @Override
      public String getValue(ObjetoDato origen) {
          return origen.getValor(actual.getNombreCampo());
      }
  };
  columna.setSortable(true);
  sortHandler.setComparator(columna, new Comparator&lt;ObjetoDato&gt;() {
      @Override
      public int compare(ObjetoDato o1, ObjetoDato o2) {
        return o1.getValor(actual.getNombreCampo()).compareTo(o2.getValor(actual.getNombreCampo()));
      }
  });
  table.addColumn(columna,header );
  </code></pre>