refs #10554 : fix extrabuttonlock also for select

extension/Classes/Core/Helper/HelperFormElement.php

@@ -432,6 +432,15 @@ EOF;
         // LOCK
         if (!$skip && HelperFormElement::booleParameter($formElement[FE_INPUT_EXTRA_BUTTON_LOCK] ?? '-')) {
             switch ($formElement[FE_TYPE]) {
+                case FE_TYPE_SELECT:
+                    $extraButton .= <<<EOF
+                    <button class="btn btn-info"
+                            onclick="$('#$id').toggleClass('qfq-disabled')">
+                        <span class="glyphicon glyphicon-lock" aria-hidden="true"></span>
+                    </button>
+                    <script>$('#$id').addClass('qfq-disabled')</script>
+EOF;
+                    break;
                 case FE_TYPE_CHECKBOX:
                 case FE_TYPE_RADIO:
                     $extraButton .= <<<EOF

less/qfq-bs.css.less

@@ -167,6 +167,7 @@ i.@{spinner_class} {
 .qfq-disabled {
   cursor: not-allowed !important;
   pointer-events: none !important;
+  background: #eee !important;
 }