--- includes/display-layout.inc
+++ includes/display-layout.inc
@@ -192,8 +192,10 @@ function panels_change_layout($form, &$form_state) {
 
   // ARGH. Lazy load of CSS is not working for some reason.
   $renderer->add_css(drupal_get_path('module', 'panels') . "/css/panels_admin.css");
-  $renderer->add_css(drupal_get_path('module', 'panels') . "/css/panels_dnd.css");
-  $renderer->add_css(drupal_get_path('module', 'ctools') . "/css/dropdown.css");
+  if (isset($form_state['input']) && isset($form_state['input']['js']) && !$form_state['input']['js']) {
+    $renderer->add_css(drupal_get_path('module', 'panels') . "/css/panels_dnd.css");
+    $renderer->add_css(drupal_get_path('module', 'ctools') . "/css/dropdown.css");
+  }
 
   // For every region that had content in the old layout, create a custom pane
   // in the new layout that represents that region.