--- a/layout/reftests/css-invalid/default-style/style.css
+++ b/layout/reftests/css-invalid/default-style/style.css
@@ -1,6 +1,5 @@
 .invalid-ref {
-  box-shadow: 0 0 1.5px 1px red;
 }
 
 .barred-ref {
 }

--- a/layout/style/forms.css
+++ b/layout/style/forms.css
@@ -620,19 +620,20 @@ optgroup:before {
 input[type="file"] > input[type="text"] {
   direction: ltr !important;
   text-align: inherit;
 }
 
 /**
  * Set default style for invalid elements.
  */
-:not(output):invalid {
+/* TODO: uncomment this with bug 609017.
+:not(output):-moz-ui-invalid {
   box-shadow: 0 0 1.5px 1px red;
-}
+}*/
 
 output:invalid {
   color: red;
 }
 
 @media print {
   input, textarea, select, button {
     -moz-user-input: none !important;