Issue #2396983 by corbacho: Header Logo with Bartik won't change in settings preview

core/themes/bartik/color/color.inc

@@ -7,7 +7,7 @@
 
 // Put the logo path into JavaScript for the live preview.
 $js_attached['#attached']['drupalSettings']['color']['logo'] = theme_get_setting('logo.url', 'bartik');
-drupal_render($js_attached);
+drupal_process_attached($js_attached);
 
 $info = array(
   // Available colors and color labels used in theme.