dden' disabled>Interrupt</button>
            <!-- interruption cannot work in the current configuration
                 because we cannot send an interrupt message when work
                 is currently underway. At that point the Worker is
                 tied up and will not receive the message. -->
          </div></legend>
          <div><textarea id="output" readonly
                         placeholder="Shell output."></textarea></div>
        </fieldset>
      </div>
    </div> <!-- #view-split -