menu dynamique resta pas actif

<div id="menu">
  <?php do { ?>
      <a href="croix_noble_list.php?ID=<?php echo $row_catégorie['ID'];?>"><?php echo $row_categorie['theme']; ?></a>
      <?php } while ($row_categorie = mysql_fetch_assoc($categorie)); ?>
</div>

/*menu gauche 2*/
#menu {
	position:relative;
	margin-top:20px;
	left:5px;
	display:block;
	width:150px;
}
#menu a, #menu a:visited {
	display:block;
	width:150px;
	height:30px;
	background-position:left top;
	background-color:transparent;
	text-align:center;
	color:#131455;
	line-height:28px;
	text-decoration:none;
	font-family:arial, sans-serif;
	font-weight:bold;
	margin-top:5px;
	background-image: url(../images/fond_menu-documentation.gif);
	font-size: 13px;
	font-style: oblique;
	background-repeat: repeat-x;
}
#menu a:hover {
	background-position:left center;
	line-height:31px;
	overflow:hidden;
	color:#FFF;
	font-size: 13px;
	font-style: oblique;
}
#menu a.active{
	color:#F00;
	background-color: #F00;
}

#menu a:hover, .seldef {
	background-position:left center;
	line-height:31px;
	overflow:hidden;
	color:#FFF;
	font-size: 13px;
	font-style: oblique;
}

<div id="menu">
  <?php do { 
      $laclasse = "";
      if($row_categorie['ID'] == $_GET['ID']){
          $laclasse = " class='seldef' ";
      }

  ?>
      <a <?php echo $laclasse; ?> href="croix_noble_list.php?ID=<?php echo $row_catégorie['ID'];?>"><?php echo $row_categorie['theme']; ?></a>
      <?php } while ($row_categorie = mysql_fetch_assoc($categorie)); ?>
</div>

<?php do { ?>
  <a href="croix_noble_pdt.php?reference=<?php echo $row_produits['reference'];?>"><?php echo $row_produits['titre']; ?></a>