diff --git a/src/Form/PageVariantFormBase.php b/src/Form/PageVariantFormBase.php
index ae2f72c..27a338b 100644
--- a/src/Form/PageVariantFormBase.php
+++ b/src/Form/PageVariantFormBase.php
@@ -12,6 +12,7 @@
 use Drupal\Core\Entity\Query\QueryFactory;
 use Drupal\Core\Form\FormState;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\panels\Plugin\DisplayVariant\PanelsDisplayVariant;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -171,10 +172,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
    * @param \Drupal\Core\Display\VariantInterface $variant_plugin
    */
   protected function setPanelsStorage(VariantInterface $variant_plugin) {
-    // We use is_a() rather than instanceof so we don't trigger the autoloader
-    // for a class that might not be present (ie. if Panels isn't enabled).
-    if (is_a($variant_plugin, '\Drupal\panels\Plugin\DisplayVariant\PanelsDisplayVariant', TRUE)) {
-      /** @var $variant_plugin \Drupal\panels\Plugin\DisplayVariant\PanelsDisplayVariant */
+    if ($variant_plugin instanceof PanelsDisplayVariant) {
       $variant_plugin->setStorage('page_manager', $this->entity->id());
     }
   }