diff --git a/include/class_session.inc b/include/class_session.inc
index 72bf901508bd08390a109398ec6b10b34e93f0f6..4bfdfdd88789b7c0e74bfdec6a079b8811ba362d 100644
--- a/include/class_session.inc
+++ b/include/class_session.inc
@@ -175,7 +175,7 @@ class session {
    */
   public static function global_delete($name)
   {
-    if ($_SESSION[$name]) {
+    if (isset($_SESSION[$name])) {
       unset($_SESSION[$name]);
     }
   }