diff --git a/src/Forms/Form.php b/src/Forms/Form.php
index 57b9fe516..be8f487ea 100644
--- a/src/Forms/Form.php
+++ b/src/Forms/Form.php
@@ -22,6 +22,7 @@ class Form extends Container implements Nette\Utils\IHtmlString
 	const EQUAL = ':equal',
 		IS_IN = self::EQUAL,
 		NOT_EQUAL = ':notEqual',
+		IS_NOT_IN = self::NOT_EQUAL,
 		FILLED = ':filled',
 		BLANK = ':blank',
 		REQUIRED = self::FILLED,