Fatal error: Uncaught Error: Undefined class constant 'ALERT' in /home/lexcomplex/domains/lex-complex.com.pl/public_html/wp-content/plugins/sticky-header-effects-for-elementor/modules/transparent/module.php:50 Stack trace: #0 /home/lexcomplex/domains/lex-complex.com.pl/public_html/wp-includes/class-wp-hook.php(305): SheHeader\Modules\Transparent\Module->register_controls(Object(Elementor\Element_Section)) #1 /home/lexcomplex/domains/lex-complex.com.pl/public_html/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters('', Array) #2 /home/lexcomplex/domains/lex-complex.com.pl/public_html/wp-includes/plugin.php(470): WP_Hook->do_action(Array) #3 /home/lexcomplex/domains/lex-complex.com.pl/public_html/wp-content/plugins/elementor/includes/base/controls-stack.php(1536): do_action('elementor/eleme...', Object(Elementor\Element_Section), Array) #4 /home/lexcomplex/domains/lex-complex.com.pl/public_html/wp-content/plugins/elementor/includes/elements/section.php(1306): Elementor\Controls_Stack->end_controls_section() #5 /home/ in /home/lexcomplex/domains/lex-complex.com.pl/public_html/wp-content/plugins/sticky-header-effects-for-elementor/modules/transparent/module.php on line 50