Index: wp-admin/css/install-rtl.css
===================================================================
--- wp-admin/css/install-rtl.css	(revision 26749)
+++ wp-admin/css/install-rtl.css	(working copy)
@@ -305,7 +305,7 @@
 		display: block;
 		max-width: none;
 		box-sizing: border-box;
-		-mox-box-sizing: border-box;
+		-moz-box-sizing: border-box;
 	}
 
 }