diff --git a/src/Plugin/Field/FieldWidget/ViewfieldWidgetSelect.php b/src/Plugin/Field/FieldWidget/ViewfieldWidgetSelect.php
new file mode 100644
index 0000000..9536b65
--- /dev/null
+++ b/src/Plugin/Field/FieldWidget/ViewfieldWidgetSelect.php
@@ -0,0 +1,305 @@
+<?php
+
+namespace Drupal\viewfield\Plugin\Field\FieldWidget;
+
+use Drupal\Core\Ajax\InvokeCommand;
+use Drupal\Core\Field\Plugin\Field\FieldWidget\OptionsSelectWidget;
+use Symfony\Component\Validator\ConstraintViolationInterface;
+use Drupal\Core\Field\FieldItemListInterface;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Ajax\AjaxResponse;
+use Drupal\Core\Ajax\HtmlCommand;
+
+/**
+ * Plugin implementation of the 'viewfield_select' widget.
+ *
+ * @FieldWidget(
+ *   id = "viewfield_select",
+ *   label = @Translation("Viewfield"),
+ *   field_types = {"viewfield"}
+ * )
+ */
+class ViewfieldWidgetSelect extends OptionsSelectWidget {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, FormStateInterface $form_state) {
+    $field_type = $this->fieldDefinition->getType();
+    $item = $items[$delta];
+
+    $element['target_id'] = parent::formElement($items, $delta, $element, $form, $form_state);
+    $element['target_id']['#field_type'] = $field_type;
+    $element['target_id']['#field_item'] = $item;
+    $element['target_id']['#description'] = $this->t('View name.');
+    $element['target_id']['#ajax'] = [
+      'callback' => [$this, 'ajaxGetDisplayOptions'],
+      'event' => 'change',
+      'progress' => [
+        'type' => 'throbber',
+        'message' => $this->t('Retrieving view displays.'),
+      ],
+    ];
+
+    // Set up options for allowed views.
+    $empty_label = $this->getEmptyLabel() ?: $this->t('- None -');
+    // Always allow '_none' for non-required fields or second and greater delta.
+    $none_option = (!$this->fieldDefinition->isRequired() || $delta > 0) ? ['_none' => $empty_label] : [];
+    $element['target_id']['#options'] = array_merge($none_option, $item->getViewOptions());
+    $element['target_id']['#multiple'] = FALSE;
+
+    // Build an array of keys to retrieve values from $form_state.
+    $form_state_keys = [$this->fieldDefinition->getName(), $delta];
+    if (!empty($form['#parents'])) {
+      $form_state_keys = array_merge($form['#parents'], $form_state_keys);
+    }
+
+    // Assign default values.
+    $default_target_id = NULL;
+    $display_id_options = NULL;
+    $default_display_id = NULL;
+    $default_arguments = NULL;
+    $default_items_to_display = NULL;
+    $item_value = $item->getValue();
+
+    // Set initial default values from the item if they exist.
+    if (isset($item_value['target_id'])) {
+      $default_target_id = $item_value['target_id'];
+      $display_id_options = $item->getDisplayOptions($item_value['target_id']);
+      $default_display_id = $item_value['display_id'];
+      $default_arguments = $item_value['arguments'];
+      $default_items_to_display = $item_value['items_to_display'];
+    }
+
+    // Set default values based on values from form_state, if they exist.
+    $values = $form_state->getValue($this->fieldDefinition->getName());
+    if (!empty($values[$delta])) {
+      $default_target_id = $values[$delta]['target_id'];
+      $default_display_id = $values[$delta]['display_id'];
+      $default_arguments = $values[$delta]['arguments'];
+      $display_id_options = $item->getDisplayOptions($default_target_id);
+      $default_items_to_display = $values[$delta]['items_to_display'];
+    }
+
+    // #default_value needs special handling, otherwise it consists of an array
+    // of values corresponding to field items, one for each #delta.
+    $element['target_id']['#default_value'] = $default_target_id;
+
+    // Construct CSS class to target ajax callback.
+    $display_id_class = $this->createDisplayClass($form_state_keys);
+
+    // Use primary target_id field to control visibility of secondary ones.
+    $field_key =  $form_state_keys[0] . '[' . implode('][', array_slice($form_state_keys, 1)) . ']';
+    $primary_field_name = $field_key . '[target_id]';
+    $primary_field_visible_test = [':input[name="' . $primary_field_name . '"]' => ['!value' => '_none']];
+
+    $element['display_id'] = [
+      '#title' => $this->t('Display'),
+      '#type' => 'select',
+      '#options' => $display_id_options,
+      '#default_value' => $default_display_id,
+      '#description' => $this->t('View display to be used.'),
+      '#attributes' => ['class' => [$display_id_class]],
+      '#weight' => 10,
+      '#states' => ['visible' => $primary_field_visible_test],
+    ];
+
+    $element['view_options'] = [
+      '#type' => 'details',
+      '#title' => $this->t('Advanced options'),
+      '#weight' => 20,
+      '#open' => false,
+      '#parents' => $form_state_keys,
+      '#states' => [
+        'open' => [
+          [':input[name="' . $field_key .'[arguments]"]' => ['filled' => TRUE]],
+          [':input[name="' . $field_key .'[items_to_display]"]' => ['filled' => TRUE]],
+        ],
+        'visible' => $primary_field_visible_test,
+      ],
+    ];
+
+    $element['view_options']['arguments'] = [
+      '#title' => $this->t('Arguments'),
+      '#type' => 'textfield',
+      '#default_value' => $default_arguments,
+      '#description' => $this->t('Separate contextual filters with a "/". Each filter may use "+" or "," for multi-value arguments.<br>This field supports tokens.'),
+      '#weight' => 20,
+      '#states' => ['visible' => $primary_field_visible_test],
+      '#maxlength' => 255,
+    ];
+
+    // Get entity types from the $items.
+    $entity_type = $items->getEntity()->getEntityTypeId();
+
+    // Token expects the value "term" for taxonomy_term entities.
+    if ($entity_type == 'taxonomy_term') {
+      $entity_type = 'term';
+    }
+
+    $element['view_options']['token_help'] = [
+      '#type' => 'item',
+      '#weight' => 30,
+      '#states' => ['visible' => $primary_field_visible_test],
+      'tokens' => [
+        '#theme' => 'token_tree_link',
+        '#token_types' => [$entity_type],
+      ],
+    ];
+
+    $element['view_options']['items_to_display'] = [
+      '#title' => $this->t('Items to display'),
+      '#type' => 'textfield',
+      '#default_value' => $default_items_to_display,
+      '#description' => $this->t('Override the number of items to display. This also disables the pager if one is configured. Leave empty for default limit.'),
+      '#weight' => 40,
+      '#states' => ['visible' => $primary_field_visible_test],
+    ];
+
+    $element['#attached']['library'][] = 'viewfield/viewfield';
+
+    return $element;
+  }
+  
+  /**
+   * {@inheritdoc}
+   */
+  protected function formMultipleElements(FieldItemListInterface $items, array &$form, FormStateInterface $form_state) {
+    $elements = parent::formMultipleElements($items, $form, $form_state);
+    // Must always show fields on configuration form.
+    if (!$this->isDefaultValueWidget($form_state) && $this->getFieldSetting('force_default')) {
+      $elements['#access'] = FALSE;
+    }
+
+    $max_delta = $elements['#max_delta'];
+    $is_multiple = $elements['#cardinality_multiple'];
+
+    if ($is_multiple) {
+      for ($delta = 0; $delta <= $max_delta; $delta++) {
+        $element = &$elements[$delta];
+        // Change title to 'View #'.
+        $element['target_id']['#title'] = $this->t('View @number', ['@number' => $delta + 1]);
+        // Force title display.
+        $element['target_id']['#title_display'] = 'before';
+      }
+    }
+    else {
+      // $max_delta == 0 for this case.
+      $element = &$elements[0];
+      // Change title to simply 'View'.
+      $element['target_id']['#title'] = $this->t('View');
+      // Wrap single values in a fieldset unless on the default settings form,
+      // as long as the field is visible (!force_default).
+      if (!$this->isDefaultValueWidget($form_state) && !$this->getFieldSetting('force_default')) {
+        $element += [
+          '#type' => 'fieldset',
+          '#title' => $this->fieldDefinition->getLabel(),
+        ];
+      }
+    }
+
+    return $elements;
+  }
+
+  /**
+   * Overridden form validation handler for widget elements.
+   *
+   * Save selected target_id as a single item, since there will be at most one.
+   * This prevents the value from being deeply nested inside $form_state.
+   *
+   * @param array $element
+   *   The form element.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state.
+   *
+   * @see OptionsWidgetBase::validateElement()
+   */
+  public static function validateElement(array $element, FormStateInterface $form_state) {
+    if ($element['#required'] && $element['#value'] == '_none') {
+      $form_state->setError($element, t('@name field is required.', ['@name' => $element['#title']]));
+    }
+
+    // Massage submitted form values.
+    // Drupal\Core\Field\WidgetBase::submit() expects values as
+    // an array of values keyed by delta first, then by column, while our
+    // widgets return the opposite.
+    if (is_array($element['#value'])) {
+      $values = array_values($element['#value']);
+    }
+    else {
+      $values = [$element['#value']];
+    }
+
+    // Filter out the 'none' option. Use a strict comparison, because
+    // 0 == 'any string'.
+    $index = array_search('_none', $values, TRUE);
+    if ($index !== FALSE) {
+      unset($values[$index]);
+    }
+
+    $target_id = !empty($values[0]) ? $values[0] : NULL;
+    $form_state->setValueForElement($element, $target_id);
+  }
+
+  public function massageFormValues(array $values, array $form, FormStateInterface $form_state) {
+    $values = parent::massageFormValues($values, $form, $form_state); // TODO: Change the autogenerated stub
+    foreach ($values as $key => $value) {
+    }
+    return $values;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function errorElement(array $element, ConstraintViolationInterface $error, array $form, FormStateInterface $form_state) {
+    $element = $element;
+    return $element['target_id'];
+  }
+
+  /**
+   * Ajax callback to retrieve display IDs.
+   *
+   * @param array $form
+   *   The form from which the display IDs are being requested.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state of the form.
+   *
+   * @return \Drupal\Core\Ajax\AjaxResponse
+   *   The Ajax response.
+   */
+  public function ajaxGetDisplayOptions(array &$form, FormStateInterface $form_state) {
+    $trigger = $form_state->getTriggeringElement();
+    $form_state_keys = array_slice($trigger['#parents'], 0, -1);
+    $form_state_value = $form_state->getValue($form_state_keys);
+    $display_options = $trigger['#field_item']->getDisplayOptions($form_state_value['target_id']);
+
+    $html = '';
+    foreach ($display_options as $key => $value) {
+      $html .= '<option value="' . $key . '">' . $value . '</option>';
+    }
+    $html = '<optgroup>' . $html . '</optgroup>';
+
+    // Create a class selector for Ajax response.
+    $selector = '.' . $this->createDisplayClass($form_state_keys);
+    $response = new AjaxResponse();
+    $response->addCommand(new HtmlCommand($selector, $html));
+    $response->addCommand(new InvokeCommand($selector, 'ajaxEnableElements'));
+    $form_state->setRebuild(TRUE);
+
+    return $response;
+  }
+
+  /**
+   * Produce a class for a display input field.
+   *
+   * @param array $components
+   *   An array of class components to be concatenated.
+   *
+   * @return string
+   *   The display input field class.
+   */
+  protected function createDisplayClass(array $components) {
+    return implode('-', $components) . '-display-id';
+  }
+
+}
diff --git a/templates/viewfield-formatter-default.html.twig b/templates/viewfield-formatter-default.html.twig
index 15fd2a9..809937f 100644
--- a/templates/viewfield-formatter-default.html.twig
+++ b/templates/viewfield-formatter-default.html.twig
@@ -11,10 +11,10 @@
  * @ingroup themeable
  */
 #}
-{% spaceless %}
+{% apply spaceless %}
   <div class="viewfield-wrapper">
     {% if output %}
         <div class="viewfield">{{ output }}</div>
     {% endif %}
   </div>
-{% endspaceless %}
+{% endapply %}
diff --git a/viewfield.info.yml b/viewfield.info.yml
index 5f25a88..bed2a19 100644
--- a/viewfield.info.yml
+++ b/viewfield.info.yml
@@ -3,6 +3,7 @@ type: module
 description: 'Defines a field type to display a view.'
 version: VERSION
 core: 8.x
+core_version_requirement: ^8 || ^9 || ^10
 dependencies:
   - views
   - field
diff --git a/viewfield.module b/viewfield.module
index 56d3c68..8c59885 100644
--- a/viewfield.module
+++ b/viewfield.module
@@ -25,7 +25,7 @@ function viewfield_theme() {
 function viewfield_preprocess_viewfield_formatter_default(&$variables) {
   $element = $variables['element'];
   $view_el = $element['#view']->preview($element['#view_display'], array($element['#view_arguments']));
-  $output = render ($view_el);
+  $output = \Drupal::service('renderer')->render($view_el);
   $variables['output'] = $output;
 }