kisabelle

<?php

// Sets the user's display name (always) to first name last name, when it's avail.
add_action ('admin_head','make_display_name_f_name_last_name');
function make_display_name_f_name_last_name(){

  $users = get_users(array('fields'=>'all'));

  foreach($users as $user){
    $user = get_userdata($user->ID);