lap.
          If set to <code>true</code> all subgroups will be stacked.
          If a value was specified for the <code>order</code> parameter in the options, that ordering will be used when stacking the items.
      </td>
    </tr>
    <tr>
      <td>title</td>
      <td>String</td>
      <td>none</td>
      <td>A title for the group, displayed when holding the mouse on the groups label.
        The title can only contain plain text.
      </td>
    </tr>
    <tr>
      <td>visible</td>
      <td>Boolea