diff --git a/src/features.coffee b/src/features.coffee
index 29696f9a7..c34b8f844 100644
--- a/src/features.coffee
+++ b/src/features.coffee
@@ -738,7 +738,7 @@ Settings =
       <img src=#{Favicon.unreadDead}>
       """
   togglecss: ->
-    if $('textarea', @parentNode.parentNode).disabled = !@checked
+    if $('textarea[name=usercss]', $.x 'ancestor::fieldset[1]', @).disabled = !@checked
       CustomCSS.rmStyle()
     else
       CustomCSS.addStyle()