/**
  * display column content
  * @param $item
  * @return mixed
  */
 function column_group($item)
 {
     $groups = AWC_WidgetFeature_saveconfig::get_groups();
     return isset($groups[$item->_group]) ? $groups[$item->_group] : $item->_group;
 }
<?php

/**
 * Created by PhpStorm.
 * User: Hoang
 * Date: 15/06/2015
 * Time: 21:06
 */
$widopt_groups = apply_filters('hw_awc_widget_saveconfig_group', AWC_WidgetFeature_saveconfig::get_groups());
//_print($t->id_base);
if (method_exists($t, 'AWC_WidgetFeature_saveconfig')) {
    //IF current widget tell you how to get it?
    $saveconfig = $t->AWC_WidgetFeature_saveconfig($instance);
} else {
    $saveconfig = $instance;
}
?>
<fieldset>
    <legend>Lưu cài đặt</legend>
    <p>Lưu ý: cần lưu widget trước khi sử dụng tính năng này.</p>
<p>
    <label for="<?php 
echo $this->get_field_id('hw_widopt_group');
?>
"><?php 
_e("Nhóm");
?>
</label><br/>
    <select class="hw_widopt_group" name="<?php 
echo $this->get_field_name('hw_widopt_group');
?>
 /**
  * @hw_hook filter hw_awc_widget_saveconfig_group
  * @param array $_group group
  * @return array
  */
 public static function _hw_awc_widget_saveconfig_group($_groups)
 {
     $groups = array(self::WIDGET_CONFIG_GROUP => 'Shortcode Widget');
     AWC_WidgetFeature_saveconfig::set_groups($groups);
     return AWC_WidgetFeature_saveconfig::get_groups();
 }