Hi,
Sorry for the late reply, and thanks for the login, so I copied your two pages to my localhost to test, and applied the css & javascript from the documentation and observed the menu “active-item” class being added & removed constantly.
This seems to lead to a performance issue, as you pointed out. So I researched this and found a better working script, which I adjusted to work with the sub-menu and css.
So the css is the same:

/* Active menu styles */
#top .submenu-onepage .active-menu-item,
#top .submenu-onepage .active-menu-item a {
background: #000 !important;
color: #FFF !important;
}



#top .submenu-onepage .av-subnav-menu > li > a {
border-left-style: none !important;
border-left-width: 0px !important;
}

Try adding this script to the end of your functions.php file in Appearance > Editor:

function custom_sub_menu_highlighting_script(){
  ?>
  <script>
(function($){
// Cache selectors
var lastId,
    topMenu = $("#sub_menu1"),
    topMenuHeight = topMenu.outerHeight()+15,
    // All list items
    menuItems = topMenu.find("a"),
    // Anchors corresponding to menu items
    scrollItems = menuItems.map(function(){
      var item = $($(this).attr("href"));
      if (item.length) { return item; }
    });

// Bind click handler to menu items
// so we can get a fancy scroll animation
menuItems.click(function(e){
  var href = $(this).attr("href"),
      offsetTop = href === "#" ? 0 : $(href).offset().top-topMenuHeight+1;
  $('html, body').stop().animate({ 
      scrollTop: offsetTop
  }, 300);
  e.preventDefault();
});

// Bind to scroll
$(window).scroll(function(){
   // Get container scroll position
   var fromTop = $(this).scrollTop()+topMenuHeight;
   
   // Get id of current scroll item
   var cur = scrollItems.map(function(){
     if ($(this).offset().top < fromTop)
       return this;
   });
   // Get the id of the current element
   cur = cur[cur.length-1];
   var id = cur && cur.length ? cur[0].id : "";
   
   if (lastId !== id) {
       lastId = id;
       // Set/remove active class
       menuItems
         .parent().removeClass("active-menu-item")
         .end().filter("[href='#"+id+"']").parent().addClass("active-menu-item");
   }                   
});
})(jQuery);
</script>
<?php
}
add_action('wp_footer', 'custom_sub_menu_highlighting_script');

In my tests this works much better and the scroll to anchor action from clicking the menu items also is much smoother, so please give this a try and if you still find a performance issue try disabling your other scripts and plugins to check for a conflict.
In the script above it looks for the ID sub_menu1 for the sub-menu here: topMenu = $("#sub_menu1")
This is the default ID for the first sub-menu on each page, so this should be fine, but if you use a custom ID for the sub-menu in the future please ensure to change this too.
I also noticed that in your child theme it looks like the other script was added twice, once in the functions.php and in menu-highlight.js, after you remove the other script please ensure the new script is only added once. I’m sure that you would, I just wanted to point that out 😉

Best regards,
Mike

Hi,

Thanks for the clarification. Please try the following in Quick CSS under Enfold->General Styling:

.search .entry-title a {
  color: #000;
}

Best regards,
Rikard

Hey pathemeforestnet,

Please try the following in Quick CSS under Enfold->General Styling:

.woocommerce-product-search button {
    background: #000;
    padding: 10px;
}

Best regards,
Rikard