`Strange WPML mobile behavior

Hi,

I use WPML for a multi language site and I have a strange problem on a mobile with selecting a language.
When I click on the language buttons nothing happens.See https://bergjeths.com on a mobile device. On a desktop it works fine.
I use the following custom css code:

/* WPML Flags Country Code */
li.menu-item.menu-item-language.menu-item-language-current.dropdown_ul_available, #header_meta ul.avia_wpml_language_switch.avia_wpml_language_switch_extra,.language_flag img {display: none !important;}
.header_color li.language_en.avia_current_lang span.language_code {text-decoration: underline; color: #ffffff !important;}
.header_color li span.language_code {color: #ffffff !important; display: block !important; text-transform: uppercase; font-size: 16px; font-weight: normal; font-family: 'Exo', 'HelveticaNeue', 'Helvetica Neue', Helvetica, Arial, sans-serif;}
#top ul.avia_wpml_language_switch li {margin: 0; padding: 0 5px; border: none; border-left: 1px solid #ffffff; height: 14px;}
#top ul.avia_wpml_language_switch li:first-child {border-left: none;}
#top ul.avia_wpml_language_switch li a {position: relative; top: -12px;}
#top ul.avia_wpml_language_switch.avia_wpml_language_switch_extra {position: absolute; top: 82px;}
#top .header-scrolled ul.avia_wpml_language_switch.avia_wpml_language_switch_extra {position: absolute; top: 15px;}
.avia-menu.av-main-nav-wrap {margin-right: 130px;}

/* WPML Flags Country Code */
@media only screen and (max-width: 990px) {
#header_main_alternate { display: block !important; border: none !important; }
#top ul.avia_wpml_language_switch.avia_wpml_language_switch_extra {position: absolute; top: 0px;}
} 

and the following PHP code in function.php:

add_action('after_setup_theme','avia_remove_main_menu_flags');
function avia_remove_main_menu_flags(){
	remove_filter( 'wp_nav_menu_items', 'avia_append_lang_flags', 20, 2 );
	remove_filter( 'avf_fallback_menu_items', 'avia_append_lang_flags', 20, 2 );
	remove_action( 'avia_meta_header', 'avia_wpml_language_switch', 10);
}

add_action('init', 'avf_add_flags');
function avf_add_flags() {
	add_action( 'ava_inside_main_menu', 'avia_wpml_language_switch', 10);
}

add_action('init','ava_remove_lang_flags', 9999);
function ava_remove_lang_flags() {
	remove_filter( 'wp_nav_menu_items', 'avia_append_lang_flags', 9998, 2 );
	remove_filter( 'avf_fallback_menu_items', 'avia_append_lang_flags', 9998, 2 );
        remove_action( 'avia_meta_header', 'avia_wpml_language_switch', 10);
        add_action('avia_after_footer_columns', 'avia_wpml_language_switch', 10);
}

I also use a widget area in the header with following code in functions.php:

add_action( 'ava_after_main_menu', 'enfold_customization_header_widget_area' );
function enfold_customization_header_widget_area() {
	dynamic_sidebar( 'header' );
}

Can you help me out on this or point me in the right direction?
THX Freek