diff --git a/htdocs/core/class/html.formother.class.php b/htdocs/core/class/html.formother.class.php
index b7971d52c53..9de656fc44e 100644
--- a/htdocs/core/class/html.formother.class.php
+++ b/htdocs/core/class/html.formother.class.php
@@ -362,8 +362,12 @@ class FormOther
         if ($conf->use_javascript_ajax)
         {
             include_once DOL_DOCUMENT_ROOT . '/core/lib/ajax.lib.php';
-            $out.= ajax_combobox($htmlname);
-            $nodatarole=' data-role="none"';
+            $htmlforcombo = ajax_combobox($htmlname);
+            if ($htmlforcombo)
+            {
+            	$out.= $htmlforcombo;
+            	$nodatarole=' data-role="none"';
+            }
         }
         // Select each sales and print them in a select input
         $out.='<select class="flat" id="'.$htmlname.'" name="'.$htmlname.'"'.$nodatarole.'>';
diff --git a/htdocs/core/lib/ajax.lib.php b/htdocs/core/lib/ajax.lib.php
index c891ee60a26..7508c214d83 100644
--- a/htdocs/core/lib/ajax.lib.php
+++ b/htdocs/core/lib/ajax.lib.php
@@ -314,7 +314,7 @@ function ajax_dialog($title,$message,$w=350,$h=150)
  * @param	string	$htmlname					Name of html select field
  * @param	array	$events						More events option. Example: array(array('method'=>'getContacts', 'url'=>dol_buildpath('/core/ajax/contacts.php',1), 'htmlname'=>'contactid', 'params'=>array('add-customer-contact'=>'disabled')))
  * @param  	int		$minLengthToAutocomplete	Minimum length of input string to start autocomplete
- * @return	string								Return html string to convert a select field into a combo
+ * @return	string								Return html string to convert a select field into a combo, or '' if feature has been disabled for some reason.
  */
 function ajax_combobox($htmlname, $events=array(), $minLengthToAutocomplete=0)
 {
@@ -323,8 +323,8 @@ function ajax_combobox($htmlname, $events=array(), $minLengthToAutocomplete=0)
 	if (! empty($conf->browser->phone)) return '';	// combobox disabled for smartphones (does not works)
 	if (! empty($conf->dol_use_jmobile)) return '';	// combobox with jmobile (does not works)
 	if (! empty($conf->global->MAIN_DISABLE_AJAX_COMBOX)) return '';
-	if (empty($conf->use_javascript_ajax)) return ''; 
-	
+	if (empty($conf->use_javascript_ajax)) return '';
+
 	/* Some properties for combobox:
 	minLengthToAutocomplete: 2,
 	comboboxContainerClass: "comboboxContainer",