diff --git a/plugins/calendar/calendar.php b/plugins/calendar/calendar.php
index dc6cd995..b676fb06 100644
--- a/plugins/calendar/calendar.php
+++ b/plugins/calendar/calendar.php
@@ -1502,6 +1502,7 @@ class calendar extends rcube_plugin
       "rcmail.set_env('deleteicon', '" . $this->api->output->env['deleteicon'] . "');\n".
       "rcmail.set_env('cancelicon', '" . $this->api->output->env['cancelicon'] . "');\n".
       "rcmail.set_env('loadingicon', '" . $this->api->output->env['loadingicon'] . "');\n".
+      "rcmail.gui_object('attachmentlist', '"  . $this->ui->attachmentlist_id . "');\n".
       "rcmail.add_label(" . json_encode($texts) . ");\n"
     );
     exit;
diff --git a/plugins/calendar/calendar_base.js b/plugins/calendar/calendar_base.js
index 0b8c904a..62f3588f 100644
--- a/plugins/calendar/calendar_base.js
+++ b/plugins/calendar/calendar_base.js
@@ -47,9 +47,6 @@ function rcube_calendar(settings)
             $.getScript('./plugins/calendar/lib/js/fullcalendar.js'),
             $.get(rcmail.url('calendar/inlineui'), function(html){ $(document.body).append(html); }, 'html')
           ).then(function() {
-            // register attachments form
-            rcmail.gui_object('attachmentlist', 'attachmentlist');
-            
             // disable attendees feature (autocompletion and stuff is not initialized)
             for (var c in rcmail.env.calendars)
               rcmail.env.calendars[c].attendees = false;
diff --git a/plugins/calendar/lib/calendar_ui.php b/plugins/calendar/lib/calendar_ui.php
index 63038e87..b4c989e6 100644
--- a/plugins/calendar/lib/calendar_ui.php
+++ b/plugins/calendar/lib/calendar_ui.php
@@ -606,6 +606,7 @@ class calendar_ui
       $this->rc->output->set_env('loadingicon', $skin_path . $attrib['loadingicon']);
 
     $this->rc->output->add_gui_object('attachmentlist', $attrib['id']);
+    $this->attachmentlist_id = $attrib['id'];
 
     return html::tag('ul', $attrib, '', html::$common_attrib);
   }