diff --git a/themes/base/menu.css b/themes/base/menu.css
index afd933586..0f01a0cae 100644
--- a/themes/base/menu.css
+++ b/themes/base/menu.css
@@ -13,7 +13,7 @@
 	padding: 0;
 	margin: 0;
 	display: block;
-	outline: none;
+	outline: 0;
 }
 .ui-menu .ui-menu {
 	position: absolute;