contextual links doesn't work with grid display in firefox

I wanted to add contextual links in a grid display for each cell, so I had a Global: Contextual Links to my fields but the gears for each cell are displayed in the same place : to the top right corner of my content area, where the gear to edit views is usually visible. And it is not possible to click to that gear, or to know to what cell it belongs to !

I tried with seven default theme, bartik and a zen theme with firefox 18.0.
But the gears are ok with chromium.

Here's an export of my simple view :

$view = new view();
$view->name = 'test';
$view->description = '';
$view->tag = 'default';
$view->base_table = 'node';
$view->human_name = 'test';
$view->core = 7;
$view->api_version = '3.0';
$view->disabled = FALSE; /* Edit this to true to make a default view disabled initially */

/* Display: Master */
$handler = $view->new_display('default', 'Master', 'default');
$handler->display->display_options['title'] = 'test';
$handler->display->display_options['use_more_always'] = FALSE;
$handler->display->display_options['access']['type'] = 'perm';
$handler->display->display_options['cache']['type'] = 'none';
$handler->display->display_options['query']['type'] = 'views_query';
$handler->display->display_options['exposed_form']['type'] = 'basic';
$handler->display->display_options['pager']['type'] = 'full';
$handler->display->display_options['pager']['options']['items_per_page'] = '10';
$handler->display->display_options['style_plugin'] = 'grid';
$handler->display->display_options['style_options']['columns'] = '2';
$handler->display->display_options['row_plugin'] = 'fields';
/* Field: Content: Delete link */
$handler->display->display_options['fields']['delete_node']['id'] = 'delete_node';
$handler->display->display_options['fields']['delete_node']['table'] = 'views_entity_node';
$handler->display->display_options['fields']['delete_node']['field'] = 'delete_node';
$handler->display->display_options['fields']['delete_node']['label'] = '';
$handler->display->display_options['fields']['delete_node']['exclude'] = TRUE;
$handler->display->display_options['fields']['delete_node']['element_label_colon'] = FALSE;
/* Field: Content: Edit link */
$handler->display->display_options['fields']['edit_node']['id'] = 'edit_node';
$handler->display->display_options['fields']['edit_node']['table'] = 'views_entity_node';
$handler->display->display_options['fields']['edit_node']['field'] = 'edit_node';
$handler->display->display_options['fields']['edit_node']['label'] = '';
$handler->display->display_options['fields']['edit_node']['exclude'] = TRUE;
$handler->display->display_options['fields']['edit_node']['element_label_colon'] = FALSE;
/* Field: Global: Contextual Links */
$handler->display->display_options['fields']['contextual_links']['id'] = 'contextual_links';
$handler->display->display_options['fields']['contextual_links']['table'] = 'views';
$handler->display->display_options['fields']['contextual_links']['field'] = 'contextual_links';
$handler->display->display_options['fields']['contextual_links']['label'] = '';
$handler->display->display_options['fields']['contextual_links']['element_label_colon'] = FALSE;
$handler->display->display_options['fields']['contextual_links']['fields'] = array(
  'comments_link' => 'comments_link',
  'delete_node' => 'delete_node',
  'edit_node' => 'edit_node',
  'title' => 0,
  'body' => 0,
);
/* Field: Content: Title */
$handler->display->display_options['fields']['title']['id'] = 'title';
$handler->display->display_options['fields']['title']['table'] = 'node';
$handler->display->display_options['fields']['title']['field'] = 'title';
$handler->display->display_options['fields']['title']['label'] = '';
$handler->display->display_options['fields']['title']['alter']['word_boundary'] = FALSE;
$handler->display->display_options['fields']['title']['alter']['ellipsis'] = FALSE;
/* Field: Content: Body */
$handler->display->display_options['fields']['body']['id'] = 'body';
$handler->display->display_options['fields']['body']['table'] = 'field_data_body';
$handler->display->display_options['fields']['body']['field'] = 'body';
$handler->display->display_options['fields']['body']['label'] = '';
$handler->display->display_options['fields']['body']['alter']['max_length'] = '600';
$handler->display->display_options['fields']['body']['alter']['trim'] = TRUE;
$handler->display->display_options['fields']['body']['element_label_colon'] = FALSE;
/* Sort criterion: Content: Post date */
$handler->display->display_options['sorts']['created']['id'] = 'created';
$handler->display->display_options['sorts']['created']['table'] = 'node';
$handler->display->display_options['sorts']['created']['field'] = 'created';
$handler->display->display_options['sorts']['created']['order'] = 'DESC';
/* Filter criterion: Content: Published */
$handler->display->display_options['filters']['status']['id'] = 'status';
$handler->display->display_options['filters']['status']['table'] = 'node';
$handler->display->display_options['filters']['status']['field'] = 'status';
$handler->display->display_options['filters']['status']['value'] = 1;
$handler->display->display_options['filters']['status']['group'] = 1;
$handler->display->display_options['filters']['status']['expose']['operator'] = FALSE;

/* Display: Page */
$handler = $view->new_display('page', 'Page', 'page');
$handler->display->display_options['defaults']['hide_admin_links'] = FALSE;
$handler->display->display_options['path'] = 'test';
$translatables['test'] = array(
  t('Master'),
  t('test'),
  t('more'),
  t('Apply'),
  t('Reset'),
  t('Sort by'),
  t('Asc'),
  t('Desc'),
  t('Items per page'),
  t('- All -'),
  t('Offset'),
  t('« first'),
  t('‹ previous'),
  t('next ›'),
  t('last »'),
  t('Page'),
);