diff --git a/src/StringTagField.php b/src/StringTagField.php
index 6bab71e..2d0c251 100644
--- a/src/StringTagField.php
+++ b/src/StringTagField.php
@@ -28,7 +28,7 @@ class StringTagField extends DropdownField
     /**
      * @var array
      */
-    public static $allowed_actions = [
+    private static $allowed_actions = [
         'suggest'
     ];