Ticket #28908: 28908.1.diff

wp-admin/js/nav-menu.js

@@ -788 +788 @@
                         $('#add-custom-links input[type="text"]').keypress(function(e){
                                 if ( e.keyCode === 13 ) {
                                         e.preventDefault();
-                                        $( '#submit-customlinkdiv' ).click();
+
+                                        /*
+                                        Workaround for Mozilla Firefox's autocomplete firing internal callbacks after the keypress event.
+                                        https://bugzilla.mozilla.org/show_bug.cgi?id=286933
+                                         */
+                                        setTimeout(function() {
+
+                                                $( '#submit-customlinkdiv' ).click();
+
+                                        }, 0);
                                 }
                         });
                 },