diff --git a/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php b/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php
index b0cbb7b..1764d9b 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/views/display/DisplayPluginBase.php
@@ -1844,6 +1844,7 @@ public function buildOptionsForm(&$form, &$form_state) {
           '#suffix' => '</div>',
         );
         $form['box']['theme'] = array(
+          '#title' => t('Theme'),
           '#type' => 'select',
           '#options' => $options,
           '#default_value' => $this->theme,