diff --git a/plugins/recaptcha/configuration_validation.php b/plugins/recaptcha/configuration_validation.php
index ecc7419bc..77fea8dc0 100644
--- a/plugins/recaptcha/configuration_validation.php
+++ b/plugins/recaptcha/configuration_validation.php
@@ -56,7 +56,7 @@
     'enable_links'         => array('rule' => array('inList', array('0', '1', '2'), true)),
 
     // The plugins below still don't support Invisible reCAPTCHA
-    'enable_forum'         => array('rule' => array('inList', array('0', '1'), true)),
+    'enable_forum'         => array('rule' => array('inList', array('0', '1', '2'), true)),
     'enable_mediagallery'  => array('rule' => array('inList', array('0', '1'), true)),
     'enable_rating'        => array('rule' => array('inList', array('0', '1'), true)),
 );
diff --git a/plugins/recaptcha/functions.inc b/plugins/recaptcha/functions.inc
index d9c6a6544..59144d7e5 100644
--- a/plugins/recaptcha/functions.inc
+++ b/plugins/recaptcha/functions.inc
@@ -250,6 +250,9 @@ function plugin_templatesetvars_recaptcha($type, &$template)
 
         if ($isInvisible) {
             $formId = RECAPTCHA_getFormId($type);
+            if (empty($formId)) {
+                COM_errorLog(__FUNCTION__ . ': undefined form id for type:"' . $type . '"');
+            }
             $code = <<<JS
 var onFormSubmit = function () {
     var form = document.getElementById('{$formId}');
@@ -680,7 +683,7 @@ function RECAPTCHA_getFormId($type) {
             break;
 
         case 'forum':
-            $formId = '';
+            $formId = 'forumform';
             break;
 
         case 'rating':