diff --git a/core/modules/views/src/Plugin/views/wizard/WizardPluginBase.php b/core/modules/views/src/Plugin/views/wizard/WizardPluginBase.php
index 412f572..946d752 100644
--- a/core/modules/views/src/Plugin/views/wizard/WizardPluginBase.php
+++ b/core/modules/views/src/Plugin/views/wizard/WizardPluginBase.php
@@ -496,14 +496,17 @@ public static function getSelected(FormStateInterface $form_state, $parents, $de
     }
 
     // If there is a user-submitted value for this element that matches one of
-    // the currently available options attached to it, use that. We need to check
-    // FormState::$input rather than $form_state->getValues() here because the
-    // triggering element often has the #limit_validation_errors property set to
-    // prevent unwanted errors elsewhere on the form. This means that the
-    // $form_state->getValues() array won't be complete. We could make it complete
-    // by adding each required part of the form to the #limit_validation_errors
-    // property individually as the form is being built, but this is difficult to
-    // do for a highly dynamic and extensible form. This method is much simpler.
+    // the currently available options attached to it, use that. However, only
+    // perform this check during the form rebuild. During the initial build
+    // after #ajax is triggered, we need to rebuild the form as it was
+    // initially. We need to check FormState::getUserInput() rather than
+    // $form_state->getValues() here because the triggering element often has
+    // the #limit_validation_errors property set to prevent unwanted errors
+    // elsewhere on the form. This means that the $form_state->getValues() array
+    // won't be complete. We could make it complete by adding each required part
+    // of the form to the #limit_validation_errors property individually as the
+    // form is being built, but this is difficult to do for a highly dynamic and
+    // extensible form. This method is much simpler.
     $user_input = $form_state->isRebuilding() ? $form_state->getUserInput() : [];
     if (!empty($user_input)) {
       $key_exists = NULL;
diff --git a/core/modules/views/src/Tests/Wizard/TaggedWithTest.php b/core/modules/views/src/Tests/Wizard/TaggedWithTest.php
index caf95be..b31e2b6 100644
--- a/core/modules/views/src/Tests/Wizard/TaggedWithTest.php
+++ b/core/modules/views/src/Tests/Wizard/TaggedWithTest.php
@@ -196,7 +196,7 @@ function testTaggedWithByNodeType() {
     $this->drupalPostForm('admin/structure/views/add', $view, t('Update "of type" choice'));
     $this->assertFieldByXpath($tags_xpath);
     $view['show[type]'] = $this->nodeTypeWithoutTags->id();
-    $this->drupalPostForm(NULL, $view, t('Update "of type" choice'));
+    $this->drupalPostForm(NULL, $view, t('Update "of type" choice (2)'));
     $this->assertNoFieldByXpath($tags_xpath);
 
     // If we add an instance of the tagging field to the second node type, the
@@ -225,7 +225,7 @@ function testTaggedWithByNodeType() {
     $this->drupalPostForm('admin/structure/views/add', $view, t('Update "of type" choice'));
     $this->assertFieldByXpath($tags_xpath);
     $view['show[type]'] = $this->nodeTypeWithoutTags->id();
-    $this->drupalPostForm(NULL, $view, t('Update "of type" choice'));
+    $this->drupalPostForm(NULL, $view, t('Update "of type" choice (2)'));
     $this->assertFieldByXpath($tags_xpath);
   }
 
diff --git a/core/modules/views/tests/src/Unit/WizardPluginBaseTest.php b/core/modules/views/tests/src/Unit/WizardPluginBaseTest.php
new file mode 100644
index 0000000..1726531
--- /dev/null
+++ b/core/modules/views/tests/src/Unit/WizardPluginBaseTest.php
@@ -0,0 +1,112 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\views\Unit\WizardPluginBaseTest.
+ */
+
+namespace Drupal\Tests\views\Unit;
+
+use Drupal\Core\Form\FormState;
+use Drupal\Tests\UnitTestCase;
+use Drupal\views\Plugin\views\wizard\WizardPluginBase;
+
+/**
+ * @coversDefaultClass \Drupal\views\Plugin\views\wizard\WizardPluginBase
+ *
+ * @group views
+ */
+class WizardPluginBaseTest extends UnitTestCase {
+
+  /**
+   * @covers ::getSelected
+   *
+   * @dataProvider providerTestGetSelected
+   */
+  public function testGetSelected($expected, $element = [], $parents = [], $user_input = [], $not_rebuilding_expected = NULL) {
+    $not_rebuilding_expected = $not_rebuilding_expected ?: $expected;
+    $form_state = new FormState();
+    $form_state->setUserInput($user_input);
+
+    $actual = WizardPluginBase::getSelected($form_state, $parents, 'the_default_value', $element);
+    $this->assertSame($not_rebuilding_expected, $actual);
+    $this->assertSame($user_input, $form_state->getUserInput());
+
+    $form_state->setRebuild();
+    $actual = WizardPluginBase::getSelected($form_state, $parents, 'the_default_value', $element);
+    $this->assertSame($expected, $actual);
+    $this->assertSame($user_input, $form_state->getUserInput());
+  }
+
+  /**
+   * Provides test data for testGetSelected().
+   */
+  public function providerTestGetSelected() {
+    $data = [];
+    // A form element with an invalid #type.
+    $data['invalid_type'] = [
+      'the_default_value',
+      [
+        '#type' => 'checkbox',
+      ],
+    ];
+    // A form element with no #options.
+    $data['no_options'] = [
+      'the_default_value',
+      [
+        '#type' => 'select',
+      ],
+    ];
+    // A valid form element with no user input.
+    $data['no_user_input'] = [
+      'the_default_value',
+      [
+        '#type' => 'select',
+        '#options' => [
+          'option1' => 'Option 1',
+        ],
+      ],
+    ];
+    // A valid form element with user input that doesn't correspond to it.
+    $data['mismatched_input'] = [
+      'the_default_value',
+      [
+        '#type' => 'select',
+        '#options' => [
+          'option1' => 'Option 1',
+        ],
+      ],
+      ['foo', 'bar'],
+      ['foo' => ['foo' => 'value1']],
+    ];
+    // A valid form element with a valid dynamic value that matches the default
+    // value.
+    $data['matching_default'] = [
+      'the_default_value',
+      [
+        '#type' => 'select',
+        '#options' => [
+          'the_default_value' => 'Option 1',
+        ],
+      ],
+      ['foo', 'bar'],
+      ['foo' => ['bar' => 'the_default_value']],
+    ];
+    // A valid form element with a valid dynamic value that does not match the
+    // default value.
+    $data['mismatched_value'] = [
+      'option1',
+      [
+        '#type' => 'select',
+        '#options' => [
+          'option1' => 'Option 1',
+        ],
+      ],
+      ['foo', 'bar'],
+      ['foo' => ['bar' => 'option1']],
+      'the_default_value',
+    ];
+    return $data;
+  }
+
+}
diff --git a/core/modules/views_ui/admin.inc b/core/modules/views_ui/admin.inc
index 30cc9c0..78be0fc 100644
--- a/core/modules/views_ui/admin.inc
+++ b/core/modules/views_ui/admin.inc
@@ -52,10 +52,6 @@ function views_ui_add_ajax_trigger(&$wrapping_element, $trigger_key, $refresh_pa
   $triggering_element = &$wrapping_element[$trigger_key];
   $triggering_element['#ajax']['callback'] = 'views_ui_ajax_update_form';
 
-  // Specify the #ajax URL in order to retain form caching.
-  // @todo Remove this in https://www.drupal.org/node/2500523.
-  //$triggering_element['#ajax']['url'] = Url::fromRoute('system.ajax');
-
   // We do not use \Drupal\Component\Utility\Html::getUniqueId() to get an ID
   // for the AJAX wrapper, because it remembers IDs across AJAX requests (and
   // won't reuse them), but in our case we need to use the same ID from request
@@ -117,9 +113,6 @@ function views_ui_add_ajax_trigger(&$wrapping_element, $trigger_key, $refresh_pa
     'wrapper' => $triggering_element['#ajax']['wrapper'],
     'trigger_key' => $trigger_key,
     'refresh_parents' => $refresh_parents,
-    // Keep track of duplicate wrappers so we don't add the same wrapper to the
-    // page more than once.
-    //'duplicate_wrapper' => !empty($seen_ids[$triggering_element['#ajax']['wrapper']]),
   );
   $seen_ids[$triggering_element['#ajax']['wrapper']] = TRUE;
   $triggering_element['#views_ui_ajax_data'] = $ajax_data;
@@ -166,9 +159,6 @@ function views_ui_add_limited_validation($element, FormStateInterface $form_stat
  * submit button form element.
  */
 function views_ui_add_ajax_wrapper($element, FormStateInterface $form_state) {
-  // Don't add the wrapper <div> if the same one was already inserted on this
-  // form.
-  if (empty($element['#views_ui_ajax_data']['duplicate_wrapper'])) {
   // Find the region of the complete form that needs to be refreshed by AJAX.
   // This was earlier stored in a property on the element.
   $complete_form = &$form_state->getCompleteForm();
@@ -188,7 +178,6 @@ function views_ui_add_ajax_wrapper($element, FormStateInterface $form_state) {
   // Copy the element that needs to be refreshed back into the form, with our
   // modifications to it.
   NestedArray::setValue($complete_form, $refresh_parents, $refresh_element);
-  }
 
   return $element;
 }