diff --git a/src/Method/FormContext.php b/src/Method/FormContext.php
index b4dd42c..565d272 100644
--- a/src/Method/FormContext.php
+++ b/src/Method/FormContext.php
@@ -9,7 +9,7 @@ class FormContext implements FormContextInterface
 {
     public bool $formSent;
     
-    public array $values;
+    public array $values = [];
 
     public array $messages = [];
     
@@ -53,7 +53,7 @@ class FormContext implements FormContextInterface
 
     public function __isset($key)
     {
-        return array_key_exists($key, $_SESSION);
+        return array_key_exists($key, $this->values);
     }
 
     public function __unset($key)