How to get active-trail classes in a megamenu?

I think I found my answer. I don't know how to do a patch, so here are the changed functions below. Both are in megamenus.utilities.inc:

/**
 * Retrieve a menu and pre-style before theming
 *
 * This function currently removes all "hidden" items, which could be
 * handled in the single iteration of the theme function.  But, I forsee
 * a need for other prep work that might be simmplfied with this second function
 *
 * Will be used in the future to add/alter attributes prior to theming
 *
 * @param $menuname
 *    The name of the menu to extract
 *
 * @return
 *    The pre-styled menu tree
 */
function _megamenu_get_menu_tree($menuname) {
  $menutree = menu_tree_all_data($menuname);
  $menutree_page = menu_tree_page_data($menuname); // Contains active trail
  foreach($menutree as $tier_1_key => $tier_1_item) {
		if ($menutree_page[$tier_1_key]['link']['in_active_trail']) {
			$menutree[$tier_1_key]['link']['in_active_trail'] = TRUE;
		}
    
		if ($tier_1_item['link']['hidden'] == 1 || empty($tier_1_item['link']['link_title'])) {
      unset($menutree[$tier_1_key]);
    }
    else {
			if ($tier_1_item['below']) {
				foreach($tier_1_item['below'] as $tier_2_key => $tier_2_item) {
					if ($menutree_page[$tier_1_key]['below'][$tier_2_key]['link']['in_active_trail']) {
						$menutree[$tier_1_key]['below'][$tier_2_key]['link']['in_active_trail'] = TRUE;
					}
					if ($tier_2_item['link']['hidden'] == 1 || empty($tier_2_item['link']['link_title'])) {
	        	unset($menutree[$tier_1_key]['below'][$tier_2_key]);
	        }
					else {
						if ($tier_2_item['below']) {
							foreach($tier_2_item['below'] as $tier_3_key => $tier_3_item) {
								if ($menutree_page[$tier_1_key]['below'][$tier_2_key]['below'][$tier_3_key]['link']['in_active_trail']) {
									$menutree[$tier_1_key]['below'][$tier_2_key]['below'][$tier_3_key]['link']['in_active_trail'] = TRUE;
								}
								
								if ($tier_3_item['link']['hidden'] ==1 || empty($tier_3_item['link']['link_title'])) {
		                unset($menutree[$tier_1_key]['below'][$tier_2_key]['below'][$tier_3_key]);
		            }
		            else if ($tier_3_item['below']){
                	unset($menutree[$tier_1_key]['below'][$tier_2_key]['below'][$tier_3_key]['below']);
            		}	
							} // end level 3 loop
						}
					}
				} // end level 2 loop
			}
		}
  } // end level 1 loop
  return $menutree;
}

/**
 * Determine if a particular mega menu item is active.
 *
 * TODO: make it better
 *
 * @param <string> $branch (of mega menu)
 */
function _megamenu_active_classes($branch) {
	if (!is_array($branch)) return '';
	
	$active = '';
	
	if ($branch['link']['in_active_trail']) {
		if  (array_key_exists('below', $branch)) {
			$active = ' active active-trail';
		}
		else {
			$active = ' active-trail';
		}
	}
	
	return $active;
}

In the original, menu_tree_page_data() is used to pull a menu array that contains active_trail info, and then it is never referenced again. My assumption is the author intended to use that active trail data. The new version references that active trail information, inserting it into the $menutree array. _megamenu_active_classes() needed modification as well to properly reference the 'below' array key.

This works, and I get active trails now in all my menus.