diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index a25fd098f9a..4bbd030b1eb 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -8123,14 +8123,22 @@ function dolGetButtonAction($label, $html = '', $actionType = 'default', $url =
         $attr['href'] = '';
     }
 
-    if(empty($id)){
+    if(!empty($id)){
         $attr['id'] = $id;
     }
 
     // Override attr
     if(!empty($params['attr']) && is_array($params['attr'])){
         foreach($params['attr'] as $key => $value){
-            $attr[$key] = $value;
+            if($key == 'class'){
+                $attr['class'].= ' '.$value;
+            }
+            elseif($key == 'classOverride'){
+                $attr['class'] = $value;
+            }
+            else{
+                $attr[$key] = $value;
+            }
         }
     }
 
@@ -8202,10 +8210,10 @@ function dolGetButtonTitle($label, $helpText = '', $iconClass = 'fa fa-file', $u
 
         $attr['href'] = '';
 
-        if($status == -1){ // Not enough permissions
+        if($status == -1){ // disable
             $attr['title'] = dol_escape_htmltag($langs->transnoentitiesnoconv("FeatureDisabled"));
         }
-        elseif($status == 0){ // disable
+        elseif($status == 0){ // Not enough permissions
             $attr['title'] = dol_escape_htmltag($langs->transnoentitiesnoconv("NotEnoughPermissions"));
         }
     }