diff --git a/plugins/system/debug/debug.php b/plugins/system/debug/debug.php
index 09612f542f9ee..f2b5ab7a7e2c6 100644
--- a/plugins/system/debug/debug.php
+++ b/plugins/system/debug/debug.php
@@ -222,6 +222,7 @@ protected function displaySession($key = '', $session = null, $id = 0)
 		if( ! $session) $session = $_SESSION;
 
 		static $html = '';
+		static $id;
 
 		if( ! is_array($session))
 		{