diff --git a/components/script/dom/webidls/HTMLFieldSetElement.webidl b/components/script/dom/webidls/HTMLFieldSetElement.webidl
index 79b8e757db8..26f319ff108 100644
--- a/components/script/dom/webidls/HTMLFieldSetElement.webidl
+++ b/components/script/dom/webidls/HTMLFieldSetElement.webidl
@@ -11,7 +11,9 @@ interface HTMLFieldSetElement : HTMLElement {
 
   //readonly attribute DOMString type;
 
+  //HTMLFormControlsCollection: https://github.com/servo/servo/issues/8566
   //readonly attribute HTMLFormControlsCollection elements;
+
   readonly attribute HTMLCollection elements;
 
   //readonly attribute boolean willValidate;