Summary setting is not displayed when value is 0

Take a look for example at:

ds/ds.ds_fields_info.inc:49

'default' => array('wrapper' => 'h2', 'link' => 0, 'class' => ''),

If link = 0 then summary wont be displayed for this link setting.

Why? because ds_ds_field_format_summary function doesnt take 0 values into account:

ds/includes/ds.field_ui.inc:1212

function ds_ds_field_format_summary($field) {
  $summary = '';
  $settings = isset($field['formatter_settings']) ? $field['formatter_settings'] : $field['properties']['default'];
  $functions = module_invoke_all('ds_field_theme_functions_info');
  foreach ($settings as $key => $value) {

    // Ignore Field Formatter conditions.
    if ($key == 'conditions') {
      continue;
    }

    if ($key == 'ctools') {
      $conf = unserialize($value);
      $summary .= t('Type: !type', array('!type' => check_plain(drupal_ucfirst(str_replace('_', ' ', $conf['subtype'])))));
    }
    elseif ($key == 'ft' || is_array($value)) {
      // Do nothing
    }
    elseif (!empty($value)) {
      $value = is_numeric($value) ? ($value ? t('Yes') : t('No')) : check_plain($value);
      $summary .= ' ' . str_replace('_', ' ', drupal_ucfirst(check_plain($key))) . ': ' . check_plain($value) . '<br />';
    }
  }

  if (empty($summary) && ($field['field_type'] == DS_FIELD_TYPE_CTOOLS)) {
    $summary .= t('Not configured yet.') . '<br />';
  }

  return $summary;
}

Look at:

elseif (!empty($value)) {