diff --git a/src/Plugin/field_group/FieldGroupFormatter/Details.php b/src/Plugin/field_group/FieldGroupFormatter/Details.php
index 8a78c6e..1740f66 100644
--- a/src/Plugin/field_group/FieldGroupFormatter/Details.php
+++ b/src/Plugin/field_group/FieldGroupFormatter/Details.php
@@ -26,10 +26,17 @@ class Details extends FieldGroupFormatterBase {
   public function preRender(&$element, $rendering_object) {
     parent::preRender($element, $rendering_object);
 
+    $is_open = $this->getSetting('open');
+    $children = Element::children($element);
+    foreach ($children as $child) {
+      if (!empty($rendering_object[$element['#group_name']][$child]['#children_errors'])) {
+        $is_open = TRUE;
+      }
+    }
     $element += array(
       '#type' => 'details',
       '#title' => Html::escape($this->t($this->getLabel())),
-      '#open' => $this->getSetting('open')
+      '#open' => $is_open,
     );
 
     if ($this->getSetting('id')) {