Issue #882772 by good_man, rooby, Andrew Answer, dawehner, merlinofchaos,...

    ),

  );

  // Allow other modules to add their own forms or modify existing ones.

  drupal_alter('views_ui_ajax_forms', $forms);

  if ($key) {

    return !empty($forms[$key]) ? $forms[$key] : NULL;

  }

  }

}

/**

 * This hooks allows you to alter the ajax form definitions for the sub-forms

 * that handle the editing of the different pieces of a view, for example

 * adding or editing fields or filters.

 *

 * Other modules may want to change existing form callbacks or add their own

 * new forms.

 *

 * @param array $forms

 *   An array of forms where the keys are keys, that are passed in via the url

 *   and are used to identify the forms, and the values are arrays of

 *   information defining the form, including the form id and the arguments.

 *

 * @see views_ui_ajax_forms()

 */

function hook_views_ui_ajax_forms_alter(&$forms) {

  // Add a new custom form for categorizing fields, filters, etc. attached to

  // the view. You would then implement the form function

  // mymodule_views_categorize_fields_form($form, &$form_state) and $form_state

  // would contain $form_state['type'] and $form_state['id'].

  // The urls that would call this form would be (both nojs and ajax versions):

  // admin/structure/views/nojs/categorise-item/<view_name>/<display_name>/<type>/<id>

  // admin/structure/views/ajax/categorise-item/<view_name>/<display_name>/<type>/<id>

  $forms['categorise-item'] = array(

    'form_id' => 'mymodule_views_categorize_fields_form',

    'args' => array('type', 'id'),

  );

  // Modify the add-item form callback.

  // You would then implement the form function

  // mymodule_add_item_form_custom(), which would override the existing

  // views_ui_add_item_form().

  // Note that you would likely use hook_form_alter() in this case instead of

  // doing this, this is just an example.

  $forms['add-item']['form_id'] = 'mymodule_add_item_form_custom';

}

/**

 * Allows altering the commands which are used on a views AJAX request.

 *