Ticket #34033: 34033-1.diff

src/wp-content/themes/twentyfifteen/js/functions.js

@@ -49 +49 @@
         // Enable menu toggle for small screens.
         ( function() {
                 var menu, widgets, social;
-                if ( ! secondary || ! button ) {
+                if ( ! secondary.length || ! button.length ) {
                         return;
                 }
 
@@ -57 +57 @@
                 menu    = secondary.find( '.nav-menu' );
                 widgets = secondary.find( '#widget-area' );
                 social  = secondary.find( '#social-navigation' );
-                if ( ! widgets.length && ! social.length && ( ! menu || ! menu.children().length ) ) {
+                if ( ! widgets.length && ! social.length && ( ! menu.length || ! menu.children().length ) ) {
                         button.hide();
                         return;
                 }