Index: privatemsg.module
===================================================================
RCS file: /cvs/drupal/contributions/modules/privatemsg/privatemsg.module,v
retrieving revision 1.70.2.30.2.91.2.93
diff -u -p -r1.70.2.30.2.91.2.93 privatemsg.module
--- privatemsg.module	10 Nov 2009 19:48:17 -0000	1.70.2.30.2.91.2.93
+++ privatemsg.module	10 Nov 2009 19:59:41 -0000
@@ -44,6 +44,8 @@ function _privatemsg_generate_user_array
   // Convert user uid list (uid1,uid2,uid3) into an array. If $slice is not NULL
   // pass that as argument to array_slice(). For example, -4 will only load the
   // last four users.
+  // This is done to avoid loading user objects that are not displayed, for
+  // obvious performance reasons.
   $users = explode(',', $userstring);
   if (!is_null($slice)) {
     $users = array_slice($users, $slice);