UserPageReorder.php

<?php
$style = '';
$userid_array = $wp_user_search->get_results();
foreach ($userid_array as $userid ) {
	$user_object = new WP_User($userid);
	$roles = $user_object->roles;
	$role = array_shift($roles);
	$userobject_array[] = $user_object;
}

function cmp($a, $b)
{
    if ($a->roles == $b->roles) {
    	if ($a->user_registered == $a->user_registered)
        	return 0;
        else{
        	return ($a->user_registered < $b->user_registered) ? 1 : -1;
        }
    }
    return ($a->roles < $b->roles) ? 1 : -1;
}

usort($userobject_array, "cmp");
foreach ($userobject_array as $user_object ) {
	$roles = $user_object->roles;
	$role = array_shift($roles);
	$style = ( ' class="alternate"' == $style ) ? '' : ' class="alternate"';
	echo "\n\t" . user_row($user_object, $style, $role);
}
?>