diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index a86a3b939a2..58f4ff9bbb4 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -5188,7 +5188,7 @@ class Form
             </a>
             <input type="hidden" class="'.$htmlname.'" name="'.$htmlname.'" value="'.$listcheckedstring.'">
             </dt>
-            <dd>
+            <dd class="dropowndd">
                 <div class="multiselectcheckbox'.$htmlname.'">
                     <ul class="ul'.$htmlname.'">
                     '.$lis.'