diff --git a/src/Form/EntityInlineForm.php b/src/Form/EntityInlineForm.php
index 91a09a5..7e05635 100644
--- a/src/Form/EntityInlineForm.php
+++ b/src/Form/EntityInlineForm.php
@@ -140,8 +140,10 @@ class EntityInlineForm implements InlineFormInterface {
    */
   public function entityForm($entity_form, FormStateInterface $form_state) {
     $operation = 'default';
-    $controller = $this->entityManager->getFormObject($entity_form['#entity']->getEntityTypeId(), $operation);
+    $controller = $this->entityManager->getFormObject($entity_form['#entity']->getEntityTypeId(), $operation, FALSE);
     $controller->setEntity($entity_form['#entity']);
+    $form_state->set(['inline_entity_form', $entity_form['#ief_id'], 'entity_form'], $controller);
+
     $child_form_state = $this->buildChildFormState($controller, $form_state, $entity_form['#entity'], $operation, $entity_form['#parents']);
 
     $entity_form = $controller->buildForm($entity_form, $child_form_state);
@@ -189,8 +191,8 @@ class EntityInlineForm implements InlineFormInterface {
       $entity = $entity_form['#entity'];
       $operation = 'default';
 
-      $controller = \Drupal::entityManager()
-        ->getFormObject($entity->getEntityTypeId(), $operation);
+      /** @var \Drupal\Core\Entity\EntityFormInterface $controller */
+      $controller = $form_state->get(['inline_entity_form', $entity_form['#ief_id'], 'entity_form']);
       $child_form_state = static::buildChildFormState($controller, $form_state, $entity, $operation, $entity_form['#parents']);
       $entity_form['#entity'] = $controller->validateForm($entity_form, $child_form_state);
 
@@ -227,7 +229,8 @@ class EntityInlineForm implements InlineFormInterface {
     /** @var \Drupal\Core\Entity\EntityInterface $entity */
     $entity = $entity_form['#entity'];
     $operation = 'default';
-    $controller = \Drupal::entityManager()->getFormObject($entity->getEntityTypeId(), $operation);
+    /** @var \Drupal\Core\Entity\EntityFormInterface $controller */
+    $controller = $form_state->get(['inline_entity_form', $entity_form['#ief_id'], 'entity_form']);
     $controller->setEntity($entity);
 
     $child_form_state = static::buildChildFormState($controller, $form_state, $entity, $operation, $entity_form['#parents']);
diff --git a/src/Plugin/Field/FieldWidget/InlineEntityFormBase.php b/src/Plugin/Field/FieldWidget/InlineEntityFormBase.php
index 4cc2db4..a6951bb 100644
--- a/src/Plugin/Field/FieldWidget/InlineEntityFormBase.php
+++ b/src/Plugin/Field/FieldWidget/InlineEntityFormBase.php
@@ -319,6 +319,11 @@ abstract class InlineEntityFormBase extends WidgetBase implements ContainerFacto
     return $element;
   }
 
+  public static function addIefValidateCallbacks($element) {
+    $element['#ief_element_validate'][] = [get_called_class(), 'validateSaveEntity'];
+    return $element;
+  }
+
   /**
    * Pre-render callback: Move form elements into fieldsets for presentation purposes.
    *
@@ -395,6 +400,38 @@ abstract class InlineEntityFormBase extends WidgetBase implements ContainerFacto
   }
 
   /**
+   * {@inheritdoc}
+   */
+  public static function validateSaveEntity($entity_form, FormStateInterface $form_state) {
+    $ief_id = $entity_form['#ief_id'];
+    $entity = $entity_form['#entity'];
+
+    if ($entity_form['#op'] == 'add') {
+      // Determine the correct weight of the new element.
+      $weight = 0;
+      $entities = $form_state->get(['inline_entity_form', $ief_id, 'entities']);
+      if (!empty($entities)) {
+        $weight = max(array_keys($entities)) + 1;
+      }
+      // Add the entity to form state, mark it for saving, and close the form.
+      $entities[] = array(
+        'entity' => $entity,
+        '_weight' => $weight,
+        'form' => NULL,
+        'needs_save' => TRUE,
+      );
+      $form_state->set(['inline_entity_form', $ief_id, 'entities'], $entities);
+    }
+    else {
+      $delta = $entity_form['#ief_row_delta'];
+      $entities = $form_state->get(['inline_entity_form', $ief_id, 'entities']);
+      $entities[$delta]['entity'] = $entity;
+      $entities[$delta]['needs_save'] = TRUE;
+      $form_state->set(['inline_entity_form', $ief_id, 'entities'], $entities);
+    }
+  }
+
+  /**
    * Checks if current submit is relevant for IEF.
    *
    * We need to save all referenced entities and extract their IDs into field
diff --git a/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php b/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php
index a7781ff..f68480a 100644
--- a/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php
+++ b/src/Plugin/Field/FieldWidget/InlineEntityFormComplex.php
@@ -318,6 +318,7 @@ class InlineEntityFormComplex extends InlineEntityFormBase implements ContainerF
 
           $element['entities'][$key]['form']['inline_entity_form']['#process'] = [
             ['\Drupal\inline_entity_form\Element\InlineEntityForm', 'processEntityForm'],
+            [get_class($this), 'addIefValidateCallbacks'],
             [get_class($this), 'addIefSubmitCallbacks'],
             [get_class($this), 'buildEntityFormActions'],
           ];
@@ -515,6 +516,7 @@ class InlineEntityFormComplex extends InlineEntityFormBase implements ContainerF
         ];
         $element['form']['inline_entity_form']['#process'] = [
           ['\Drupal\inline_entity_form\Element\InlineEntityForm', 'processEntityForm'],
+          [get_class($this), 'addIefValidateCallbacks'],
           [get_class($this), 'addIefSubmitCallbacks'],
           [get_class($this), 'buildEntityFormActions'],
         ];
@@ -655,6 +657,10 @@ class InlineEntityFormComplex extends InlineEntityFormBase implements ContainerF
         $item['target_id'] = $item['entity']->id();
         $items[] = $item;
       }
+      else {
+        $item['target_id'] = NULL;
+        $items[] = $item;
+      }
     }
 
     // Sort items by _weight.