diff --git a/mozilla/toolkit/content/xul.css b/mozilla/toolkit/content/xul.css
index 8440d0c9038..89b2b40255c 100644
--- a/mozilla/toolkit/content/xul.css
+++ b/mozilla/toolkit/content/xul.css
@@ -19,7 +19,7 @@
 
 /* hide the content, but don't destroy the frames.  Make sure this
 comes before any rules involving "hidden"  */
-*[collapsed="true"] {
+*[collapsed="true"], *[moz-collapsed="true"] {
   visibility: collapse;
 }