@@ -82,7 +82,7 @@ public function __construct($formGroupName, $elemId = null)
         // Process form
         $error = null;
         if (isset($_POST['submit_save']) && $_POST['submit_save'] == $formGroupName) {
-            $this->processPageSettings($formDisplay, $cf, $error);
+            $error = $this->processPageSettings($formDisplay, $cf);
         }
 
         // Display forms
@@ -92,14 +92,13 @@ public function __construct($formGroupName, $elemId = null)
     /**
      * Process response to form
      *
-     * @param FormDisplay  $formDisplay Form
-     * @param ConfigFile   $cf          Configuration file
-     * @param Message|null $error       Error message
+     * @param FormDisplay $formDisplay Form
+     * @param ConfigFile  $cf          Configuration file
      */
-    private function processPageSettings(&$formDisplay, &$cf, &$error): void
+    private function processPageSettings(FormDisplay $formDisplay, ConfigFile $cf): ?Message
     {
         if (! $formDisplay->process(false) || $formDisplay->hasErrors()) {
-            return;
+            return null;
         }
 
         // save settings
@@ -111,7 +110,7 @@ private function processPageSettings(&$formDisplay, &$cf, &$error): void
             exit;
         }
 
-        $error = $result;
+        return $result;
     }
 
     /**
@@ -120,7 +119,7 @@ private function processPageSettings(&$formDisplay, &$cf, &$error): void
      * @param FormDisplay  $formDisplay Form
      * @param Message|null $error       Error message
      */
-    private function storeError(&$formDisplay, &$error): void
+    private function storeError(FormDisplay $formDisplay, ?Message $error): void
     {
         $retval = '';
         if ($error) {
@@ -141,12 +140,10 @@ private function storeError(&$formDisplay, &$error): void
     /**
      * Display page-related settings
      *
-     * @param FormDisplay $formDisplay Form
-     * @param Message     $error       Error message
-     *
-     * @return string
+     * @param FormDisplay  $formDisplay Form
+     * @param Message|null $error       Error message
      */
-    private function getPageSettingsDisplay(&$formDisplay, &$error)
+    private function getPageSettingsDisplay(FormDisplay $formDisplay, ?Message $error): string
     {
         $response = ResponseRenderer::getInstance();
 
@@ -165,20 +162,16 @@ private function getPageSettingsDisplay(&$formDisplay, &$error)
 
     /**
      * Get HTML output
-     *
-     * @return string
      */
-    public function getHTML()
+    public function getHTML(): string
     {
         return $this->HTML;
     }
 
     /**
      * Get error HTML output
-     *
-     * @return string
      */
-    public function getErrorHTML()
+    public function getErrorHTML(): string
     {
         return $this->errorHTML;
     }
 
@@ -644,14 +644,6 @@
       <code>$result['Sql_queries'][]</code>
     </MixedArrayAssignment>
   </file>
-  <file src="libraries/classes/Config/PageSettings.php">
-    <PossiblyNullArgument occurrences="1">
-      <code>$error</code>
-    </PossiblyNullArgument>
-    <ReferenceConstraintViolation occurrences="1">
-      <code>return $retval;</code>
-    </ReferenceConstraintViolation>
-  </file>
   <file src="libraries/classes/Config/ServerConfigChecks.php">
     <MixedAssignment occurrences="1">
       <code>$loginCookieValidity</code>