Index: wp-admin/css/wp-admin-rtl.dev.css
===================================================================
--- wp-admin/css/wp-admin-rtl.dev.css	(revision 19456)
+++ wp-admin/css/wp-admin-rtl.dev.css	(working copy)
@@ -634,6 +634,11 @@
 	left: 20px;
 }
 
+.welcome-panel .welcome-panel-close:before {
+	left: auto;
+	right: -12px;
+}
+
 .welcome-panel .wp-badge {
 	float: right;
 }