Comment modifier le menu de GetSimple

<?php 
/*
Plugin Name: My Navigation
Description: This is a theme function that add class="button" on navigation for your theme; this is a revisit of get_navigation() code
Version: 0.1
Author: Philippe DONNART
Author URI: https://www.donnart.fr
*/

# get correct id for plugin
$thisfile=basename(__FILE__, ".php");
 
# register plugin
register_plugin(
	$thisfile, //Plugin id
	'My Navigation', 	//Plugin name
	'1.0', 		//Plugin version
	'Philippe DONNART',  //Plugin author
	'https://www.donnart.fr/', //author website
	'Add class="button" on balise a for theme Indivisible ', //Plugin description
	'theme', //page type - on which admin tab to display
	'get_my_navigation'  //main function (administration)
);

/**
 * Get Main Navigation
 *
 * This will return unordered list of main navigation
 * This function uses the menu opitions listed within the 'Edit Page' control panel screen
 *
 * @since 1.0
 * @uses GSDATAOTHERPATH
 * @uses getXML
 * @uses subval_sort
 * @uses find_url
 * @uses strip_quotes 
 * @uses exec_filter 
 *
 * @param string $currentpage This is the ID of the current page the visitor is on
 * @param string $classPrefix Prefix that gets added to the parent and slug classnames
 * @return string 
 */	
function get_my_navigation($currentpage,$classPrefix = "") {

	$menu = '';

	global $pagesArray;
	
	$pagesSorted = subval_sort($pagesArray,'menuOrder');
	if (count($pagesSorted) != 0) { 
		foreach ($pagesSorted as $page) {
			$sel = ''; $classes = '';
			$url_nav = $page['url'];
			
			if ($page['menuStatus'] == 'Y') { 
				$parentClass = !empty($page['parent']) ? $classPrefix.$page['parent'] . " " : "";
				$classes = trim( $parentClass.$classPrefix.$url_nav);
				if ("$currentpage" == "$url_nav") $classes .= " current active";
				if ($page['menu'] == '') { $page['menu'] = $page['title']; }
				if ($page['title'] == '') { $page['title'] = $page['menu']; }
				$menu .= '<li class="'. $classes .'"><a href="'. find_url($page['url'],$page['parent']) . '" title="'. encode_quotes(cl($page['title'])) .'" class="button">'.strip_decode($page['menu']).'</a></li>'."\n";
			}
		}
		
	}
	
	echo exec_filter('menuitems',$menu);
}
?>