added missing classes to backend styling

Author: Ephraim Härer

Classes/PageLayoutView/ShortcutPreviewRenderer.php

@@ -93,7 +93,7 @@ public function renderPageModulePreviewContent(GridColumnItem $item): string
             foreach ($shortCutRenderItems as $shortcutRecord) {
                 $shortcutItem = GeneralUtility::makeInstance(GridColumnItem::class, $item->getContext(), $item->getColumn(), $shortcutRecord);
                 $preview .= '<p class="pt-2 small"><b><a href="' . $shortcutItem->getEditUrl() . '">' . $this->getLanguageService()->sL('LLL:EXT:backend/Resources/Private/Language/locallang_layout.xlf:edit') . '</a></b></p>';
-                $preview .= '<div class="mb-2 p-2 border reference">' . $shortcutItem->getPreview() . '<div class="reference-overlay bg-primary-subtle opacity-25 position-absolute top-0 start-0 w-100 h-100 pe-none"></div></div>';
+                $preview .= '<div class="mb-2 p-2 border position-relative reference">' . $shortcutItem->getPreview() . '<div class="reference-overlay bg-primary-subtle opacity-25 position-absolute top-0 start-0 w-100 h-100 pe-none"></div></div>';
             }
             return $preview;
         }