diff --git a/mozilla/xpfe/components/sidebar/resources/sidebarOverlay.css b/mozilla/xpfe/components/sidebar/resources/sidebarOverlay.css
index e1d1e406184..75283e8a0a1 100644
--- a/mozilla/xpfe/components/sidebar/resources/sidebarOverlay.css
+++ b/mozilla/xpfe/components/sidebar/resources/sidebarOverlay.css
@@ -149,5 +149,5 @@ box#title-box {
 }
 
 *[collapsed="true"] {
-  visibility: collapsed;
+  visibility: collapse;
 }