diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index 2ec32218451..e6ac5631ad6 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -1406,7 +1406,7 @@ class Form
                 $outval='';
 
                 $opt = '<option value="'.$objp->idprodfournprice.'"';
-                if ($selected == $objp->idprodfournprice) $opt.= ' selected="selected"';
+                if ($selected && $selected == $objp->idprodfournprice) $opt.= ' selected="selected"';
                 if ($objp->fprice == '') $opt.=' disabled="disabled"';
                 $opt.= '>';