Fatal error: Uncaught Error: Class "WP_Widget" not found in C:\Apache24\htdocs\wp-content\plugins\photo-gallery\admin\controllers\WidgetSlideshow.php:6 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\wp-content\plugins\photo-gallery\admin\controllers\WidgetSlideshow.php on line 6