diff --git a/workflow/engine/classes/class.api.php b/workflow/engine/classes/class.api.php
index 4a546e741..f95ac90b4 100644
--- a/workflow/engine/classes/class.api.php
+++ b/workflow/engine/classes/class.api.php
@@ -7,7 +7,7 @@ class Api
 
     public function __costruct()
     {
-        $this->workspace = null;
+        self::$workspace = null;
     }
 
     public static function setWorkspace($workspace)