/**
  * @param string $name
  * @param null   $txt
  * @param null   $position
  * @param bool   $visible
  * @param bool   $custom_field
  * @param bool   $sortable
  * @param bool   $has_filter
  */
 function __construct($name = "", $txt = NULL, $position = NULL, $visible = false, $custom_field = false, $sortable = false, $has_filter = false)
 {
     $this->sortable = $sortable;
     $this->has_filter = $has_filter;
     parent::__construct($name, $txt, $position, $visible, $custom_field);
 }