Now $table->head of admin/user.php is fixed as "Firstname / Lastname".
We need to change this title order depends on $CFG->fullnamedisplay as below.

Index: user.php
===================================================================
RCS file: /cvsroot/moodle/moodle/admin/user.php,v
retrieving revision 1.108
diff -u -r1.108 user.php
--- user.php 30 Apr 2007 17:08:41 -0000 1.108
+++ user.php 24 Jul 2007 10:34:08 -0000
@@ -303,7 +303,20 @@
 
         $mainadmin = get_admin();
 
- $table->head = array ("$firstname / $lastname", $email, $city, $country, $lastaccess, "", "", "");
+ $override->firstname = 'firstname';
+ $override->lastname = 'lastname';
+ $fullnamelanguage = get_string('fullnamedisplay', '', $override);
+ if ($CFG->fullnamedisplay == 'firstname lastname') {
+ $table->head = array ("$firstname / $lastname", $email, $city, $country, $lastaccess, "", "", "");
+ } else if ($CFG->fullnamedisplay == 'language') {
+ if ($fullnamelanguage == 'firstname lastname') {
+ $table->head = array ("$firstname / $lastname", $email, $city, $country, $lastaccess, "", "", "");
+ } else {
+ $table->head = array ("$lastname / $firstname", $email, $city, $country, $lastaccess, "", "", "");
+ }
+ } else {
+ $table->head = array ("$lastname / $firstname", $email, $city, $country, $lastaccess, "", "", "");
+ }
         $table->align = array ("left", "left", "left", "left", "left", "center", "center", "center");
         $table->width = "95%";
         foreach ($users as $user) {