diff --git a/Classes/Core/Runtime/FormRuntime.php b/Classes/Core/Runtime/FormRuntime.php
index c0ba106..8c8025a 100644
--- a/Classes/Core/Runtime/FormRuntime.php
+++ b/Classes/Core/Runtime/FormRuntime.php
@@ -267,6 +267,11 @@ protected function mapAndValidatePage(Page $page)
         $pageFormValues = [];
         foreach ($page->getElementsRecursively() as $element) {
             $value = Arrays::getValueByPath($requestArguments, $element->getIdentifier());
+
+            if ($value === null) {
+                continue;
+            }
+
             $element->onSubmit($this, $value);
 
             $pageFormValues[$element->getIdentifier()] = $value;