diff --git a/plugins/zipdownload/zipdownload.php b/plugins/zipdownload/zipdownload.php
index bed92fd25..401a3094e 100644
--- a/plugins/zipdownload/zipdownload.php
+++ b/plugins/zipdownload/zipdownload.php
@@ -111,7 +111,8 @@ class zipdownload extends rcube_plugin
             $menu[] = html::tag('li', null, $rcmail->output->button(array(
                     'command'  => "download-$type",
                     'label'    => "zipdownload.download$type",
-                    'classact' => 'active',
+                    'class'    => "download $type",
+                    'classact' => "download $type active",
                     'type'     => 'link',
             )));
         }