public static function allCapabilities()
{
global $wp_roles;
$merge = array();
$roles = $wp_roles->get_names();
foreach ($roles as $key => $rolename) {
$role = get_role($key);
$merge = array_merge($merge, $role->capabilities);
}
$result = array_keys($merge);
sort($result);
$result = array_combine($result, $result);
return $result;
}