Fatal error: Uncaught Error: Class 'WP_Customize_Panel' not found in /home/visiolm/www/wp-includes/customize/class-wp-customize-nav-menus-panel.php:19
Stack trace:
#0 {main}
thrown in /home/visiolm/www/wp-includes/customize/class-wp-customize-nav-menus-panel.php on line 19