Small code improvement

program/lib/Roundcube/rcube_message.php

@@ -107,7 +107,7 @@ class rcube_message
             'prefer_html' => $this->app->config->get('prefer_html'),
             'get_url'     => $this->app->url(array(
                     'action' => 'get',
-                'mbox'   => $this->storage->get_folder(),
+                    'mbox'   => $this->folder,
                     'uid'    => $uid))
         );
 
@@ -1038,5 +1038,4 @@ class rcube_message
     {
         return rcube_mime::format_flowed($text, $length);
     }
-
 }