Index: sites/all/modules/user_stats/views/views_handler_filter_is_online.inc
===================================================================
--- sites/all/modules/user_stats/views/views_handler_filter_is_online.inc	(revision 2129)
+++ sites/all/modules/user_stats/views/views_handler_filter_is_online.inc	(working copy)
@@ -12,7 +12,8 @@
  */
 class views_handler_filter_is_online extends views_handler_filter_boolean_operator {
   function query() {
-    $sql = "(". time() ." - users.access) < 900";
+    $not = $this->value ? '' : 'NOT';
+    $sql = $not . "(". time() ." - users.access) < 900";
     $this->ensure_my_table();
     $this->query->add_where($this->options['group'], $sql);
     $this->field_alias = $this->table_alias .'_'. $this->field;