Added warning message at beginning of gradebook weights screen

main/gradebook/gradebook_edit_all.php

@@ -165,6 +165,10 @@ if ($my_api_cidreq=='') {
 <div class="actions">
 <a href="<?php echo Security::remove_XSS($_SESSION['gradebook_dest']).'?id_session='.api_get_session_id().'&amp;'.$my_api_cidreq ?>&selectcat=<?php echo $category_id ?>"> <?php echo Display::return_icon('back.png',get_lang('FolderView'),'','32'); ?></a>
 </div>
+<?php
+$warning_message = sprintf(get_lang('TotalWeightMustBeX'), $my_category['weight']);
+Display::display_normal_message($warning_message,false);
+?>
 <form method="post" action="gradebook_edit_all.php?id_session=<?php echo $_SESSION['id_session'].'&amp;'.$my_api_cidreq ?>&selectcat=<?php echo $category_id?>">
 <table class="data_table">
 		 <tr class="row_odd">