diff --git a/extension/qfq/qfq/Constants.php b/extension/qfq/qfq/Constants.php
index 72897ba0081dbe8f14a3055d2ed0fda0fa109fd9..d9024596133c9a3b160d2957ae1cb672d14a7e39 100644
--- a/extension/qfq/qfq/Constants.php
+++ b/extension/qfq/qfq/Constants.php
@@ -129,6 +129,7 @@ const ERROR_UNKNOWN_SQL_LOG_MODE = 1051;
 const ERROR_FORM_NOT_FOUND = 1052;
 const ERROR_DATE_TIME_FORMAT_NOT_RECOGNISED = 1053;
 const ERROR_SANATIZE_INVALID_VALUE = 1054;
+const ERROR_REQUIRED_VALUE_EMPTY = 1055;
 
 // Store
 const ERROR_STORE_VALUE_ALREADY_CODPIED = 1100;
diff --git a/extension/qfq/qfq/store/FillStoreForm.php b/extension/qfq/qfq/store/FillStoreForm.php
index 4f29ef5a2c603a86a6ce608c17df2d813d94adf4..f01b6121aa9a9091f696b45cbc88695a0f601382 100644
--- a/extension/qfq/qfq/store/FillStoreForm.php
+++ b/extension/qfq/qfq/store/FillStoreForm.php
@@ -106,12 +106,18 @@ class FillStoreForm {
                 continue;
             }
 
+            if ($formElement['mode'] === FE_MODE_REQUIRED) {
+                if (!isset($clientValues[$clientFieldName]) || ($clientValues[$clientFieldName] === '')) {
+                    throw new UserFormException("Missing required value.", ERROR_REQUIRED_VALUE_EMPTY);
+                }
+            }
+
             switch ($formElement['mode']) {
-                case FE_MODE_SHOW:
                 case FE_MODE_REQUIRED:
-                    if (isset($clientValues[$clientFieldName]) && ($clientValues[$clientFieldName] != '')) {
+                case FE_MODE_SHOW:
+                    if (isset($clientValues[$clientFieldName])) {
 
-                        // SELECT with multiple values, or Multi CHECKBOX are delivered as array: implode them
+                        // SELECT MULTI or CHECKBOX MULTI: delivered as array - implode them.
                         if (is_array($clientValues[$clientFieldName])) {
                             // E.g. Checkboxes needs a 'HIDDEN' HTML input to detect 'unset' of values. These 'HIDDEN' element
                             //  needs to be removed, if there is at least one checkbox is checked (=submitted)
@@ -121,18 +127,8 @@ class FillStoreForm {
                             $clientValues[$clientFieldName] = implode(',', $clientValues[$clientFieldName]);
                         }
 
-//                        try {
-                            $newValues[$formElement['name']] = Sanitize::sanitize($clientValues[$clientFieldName],
-                                $formElement['checkType'], $formElement['checkPattern'], SANATIZE_EXCEPTION);
-//                        } catch (UserFormException $e) {
-//                            $msg = "Form element '" . $formElement['name'] . ' / ' . $formElement['label'] . "': " . $e->formatMessage();
-//                            throw new UserFormException($msg, ERROR_SANATIZE_INVALID_VALUE);
-//                        }
-                    } else {
-                        if ($formElement['mode'] === FE_MODE_REQUIRED) {
-                            throw new UserFormException("Missing required value for '" . $formElement['name'] . ' / ' .
-                                $formElement['label'] . "'", ERROR_UNKNOWN_MODE);
-                        }
+                        $newValues[$formElement['name']] = Sanitize::sanitize($clientValues[$clientFieldName],
+                            $formElement['checkType'], $formElement['checkPattern'], SANATIZE_EXCEPTION);
                     }
                     break;