--- /dev/null
+<?php
+
+namespace Drupal\views_ui\Form\Ajax;
+
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\views\Views;
+use Drupal\views\ViewEntityInterface;
+use Drupal\views\ViewExecutable;
+
+/**
+ * Provides a form for configuring grouping information for a Views UI handler.
+ */
+class ConfigHandlerGroup extends ViewsFormBase {
+
+ /**
+ * Constructs a new ConfigHandlerGroup object.
+ */
+ public function __construct($type = NULL, $id = NULL) {
+ $this->setType($type);
+ $this->setID($id);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getFormKey() {
+ return 'handler-group';
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getForm(ViewEntityInterface $view, $display_id, $js, $type = NULL, $id = NULL) {
+ $this->setType($type);
+ $this->setID($id);
+ return parent::getForm($view, $display_id, $js);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function getFormId() {
+ return 'views_ui_config_item_group_form';
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function buildForm(array $form, FormStateInterface $form_state) {
+ $view = $form_state->get('view');
+ $display_id = $form_state->get('display_id');
+ $type = $form_state->get('type');
+ $id = $form_state->get('id');
+
+ $form = [
+ 'options' => [
+ '#tree' => TRUE,
+ '#theme_wrappers' => ['container'],
+ '#attributes' => ['class' => ['scroll'], 'data-drupal-views-scroll' => TRUE],
+ ],
+ ];
+ $executable = $view->getExecutable();
+ if (!$executable->setDisplay($display_id)) {
+ $form['markup'] = ['#markup' => $this->t('Invalid display id @display', ['@display' => $display_id])];
+ return $form;
+ }
+
+ $executable->initQuery();
+
+ $item = $executable->getHandler($display_id, $type, $id);
+
+ if ($item) {
+ $handler = $executable->display_handler->getHandler($type, $id);
+ if (empty($handler)) {
+ $form['markup'] = ['#markup' => $this->t("Error: handler for @table > @field doesn't exist!", ['@table' => $item['table'], '@field' => $item['field']])];
+ }
+ else {
+ $handler->init($executable, $executable->display_handler, $item);
+ $types = ViewExecutable::getHandlerTypes();
+
+ $form['#title'] = $this->t('Configure aggregation settings for @type %item', ['@type' => $types[$type]['lstitle'], '%item' => $handler->adminLabel()]);
+
+ $handler->buildGroupByForm($form['options'], $form_state);
+ $form_state->set('handler', $handler);
+ }
+
+ $view->getStandardButtons($form, $form_state, 'views_ui_config_item_group_form');
+ }
+ return $form;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function submitForm(array &$form, FormStateInterface $form_state) {
+ $view = $form_state->get('view');
+ $item = &$form_state->get('handler')->options;
+ $type = $form_state->get('type');
+
+ $handler = Views::handlerManager($type)->getHandler($item);
+ $executable = $view->getExecutable();
+ $handler->init($executable, $executable->display_handler, $item);
+
+ $handler->submitGroupByForm($form, $form_state);
+
+ // Store the item back on the view
+ $executable->setHandler($form_state->get('display_id'), $form_state->get('type'), $form_state->get('id'), $item);
+
+ // Write to cache
+ $view->cacheSet();
+ }
+
+}