Fatal error: Uncaught Error: Class 'WP_Widget' not found in C:\xampp\htdocs\wp-content\plugins\smart-slider-3\Nextend\SmartSlider3\Platform\WordPress\Widget\WidgetSmartSlider3.php:13 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\smart-slider-3\Nextend\SmartSlider3\Platform\WordPress\Widget\WidgetSmartSlider3.php on line 13