Fatal error: Uncaught Error: Class "WP_Customize_Panel" not found in /home/marketpl/public_html/marketpl_dev/functions_back2812.php/customize/class-wp-customize-nav-menus-panel.php:19 Stack trace: #0 {main} thrown in /home/marketpl/public_html/marketpl_dev/functions_back2812.php/customize/class-wp-customize-nav-menus-panel.php on line 19