undefined 'hidden' widget

After adding a serialized field and viewing a the Manage Fields page I was getting:

Notice: Undefined index: hidden in field_ui_field_overview_form()

It is related the the widget being set to a nonexistent 'hidden' widget.

In the module you define 'serialized_hidden' as a widget like bellow:

/**
 * Implements hook_field_widget_info().
 */
function serialized_field_field_widget_info() {

  $info = array();

  $info['serialized_hidden'] = array(
    'label' => t('Hidden (Alterable)'),
    'field types' => array('serialized'),
  );

  return $info;
}

But in serialized_field_field_info() you have: 'default_widget' => 'hidden',

That line should be changed to 'default_widget' => 'serialized_hidden',

I hope I understood that issue correctly. Patch forcomming.

Cheers