diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index 4be8c74ffac..6f911260afd 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -6032,6 +6032,12 @@ class Form
 			}
 			if ($tmpfieldstoshow) $fieldstoshow = $tmpfieldstoshow;
 		}
+        else
+        {
+			// For backward compatibility
+			$objecttmp->fields['ref']=array('type'=>'varchar(30)', 'label'=>'Ref', 'showoncombobox'=>1); 
+        }
+
 		if (empty($fieldstoshow))
 		{
 			if (isset($objecttmp->fields['ref'])) {