Symfony generate several forms with a twig loop

Can anybody tell me why this code is not working, I do not find an example of this on internet.

{% for dp in dpList %}
            <tr>
              <td> //values </td>
              <td>....</td>
               ...
              <td>
                {{ form_start(display) }}
                {{ form_row(display.info, { value: dp.info }) }}
                {{ form_rest(display) }}
                {{ form_end(display) }}
              </td>
            </tr>
          {% endfor %}

What I am trying to do is to show a button "Display" for each row which contains a hidden value of this row. It actually only shows the button into the first row.

Thanks!