diff --git a/core/modules/config_translation/src/FormElement/ElementInterface.php b/core/modules/config_translation/src/FormElement/ElementInterface.php
index 4f3db25..a3cc1d6 100644
--- a/core/modules/config_translation/src/FormElement/ElementInterface.php
+++ b/core/modules/config_translation/src/FormElement/ElementInterface.php
@@ -40,94 +40,14 @@
   public function getElements(LanguageInterface $source_language, LanguageInterface $translation_language, $source_config, $translation_config, $base_key, $parents);
 
   /**
-   * Returns the source element for a given configuration definition.
-   *
-   * This can be either a render array that actually outputs the source values
-   * directly or a read-only form element with the source values depending on
-   * what is considered to provide a more intuitive user interface for the
-   * translator.
-   *
-   * @param \Drupal\Core\Language\LanguageInterface $source_language
-   *   Thee source language of the configuration object.
-   * @param mixed $source_config
-   *   The configuration value of the element in the source language.
-   *
-   * @return array
-   *   A render array for the source value.
-   */
-  public function getSourceElement(LanguageInterface $source_language, $source_config);
-
-  /**
-   * Returns the translation form element for a given configuration definition.
-   *
-   * For complex data structures (such as mappings) that are translatable
-   * wholesale but contain non-translatable properties, the form element is
-   * responsible for checking access to the source value of those properties. In
-   * case of formatted text, for example, access to the source text format must
-   * be checked. If the translator does not have access to the text format, the
-   * textarea must be disabled and the translator may not be able to translate
-   * this particular configuration element. If the translator does have access
-   * to the text format, the element must be locked down to that particular text
-   * format; in other words, the format may not be changed by the translator
-   * (because the text format property is not itself translatable).
-   *
-   * In addition, the form element is responsible for checking whether the
-   * value of such non-translatable properties in the translated configuration
-   * is equal to the corresponding source values. If not, that means that the
-   * source value has changed after the translation was added. In this case -
-   * again - the translation of this element must be disabled if the translator
-   * does not have access to the source value of the non-translatable property.
-   * For example, if a formatted text element, whose source format was plain
-   * text when it was first translated, gets changed to the full HTML format,
-   * simply changing the format of the translation would lead to an XSS
-   * vulnerability as the translated text, that was intended to be escaped,
-   * would now be displayed unescaped. Thus, if the translator does not have
-   * access to the Full HTML format, the translation for this particular element
-   * may not be updated at all (the textarea must be disabled). Only if access
-   * to the Full HTML format is granted, an explicit translation taking into
-   * account the updated source value(s) may be submitted.
-   *
-   * In the specific case of formatted text this logic is implemented by
-   * utilizing a form element of type 'text_format' and its #format and
-   * #allowed_formats properties. The access logic explained above is then
-   * handled by the 'text_format' element itself, specifically by
-   * filter_process_format(). In case such a rich element is not available for
-   * translation of complex data, similar access logic must be implemented
-   * manually.
-   *
-   * @param \Drupal\Core\Language\LanguageInterface $language
-   *   The language to display the translation form for.
-   * @param mixed $source_config
-   *   The configuration value of the element in the source language.
-   * @param mixed $translation_config
-   *   The configuration value of the element in the language to translate to.
-   *
-   * @return array
-   *   Form API array to represent the form element.
-   *
-   * @see \Drupal\config_translation\FormElement\TextFormat
-   * @see filter_process_format()
-   */
-  public function getTranslationElement(LanguageInterface $language, $source_config, $translation_config);
-
-  /**
    * Sets configuration based on a nested form value array.
    *
    * @param \Drupal\Core\Config\Config $base_config
    *   Base configuration values, in the source language.
    * @param \Drupal\language\Config\LanguageConfigOverride $config_translation
    *   Translation configuration override data.
-   * @param array $config_values
-   *   A simple one dimensional or recursive array:
-   *     - simple:
-   *        array(name => array('translation' => 'French site name'));
-   *     - recursive:
-   *        cancel_confirm => array(
-   *          cancel_confirm.subject => array('translation' => 'Subject'),
-   *          cancel_confirm.body => array('translation' => 'Body content'),
-   *        );
-   *   Either format is used, the nested arrays are just containers and not
-   *   needed for saving the data.
+   * @param mixed $config_values
+   *   The configuration value of the element taken from the form values.
    * @param string|null $base_key
    *   (optional) The base key that the schema and the configuration values
    *   belong to. This should be NULL for the top-level configuration object and
@@ -137,6 +57,6 @@ public function getTranslationElement(LanguageInterface $language, $source_confi
    * @return array
    *   Translation configuration override data.
    */
-  public function setConfig(Config $base_config, LanguageConfigOverride $config_translation, array $config_values, $base_key = NULL);
+  public function setConfig(Config $base_config, LanguageConfigOverride $config_translation, $config_values, $base_key = NULL);
 
 }
diff --git a/core/modules/config_translation/src/FormElement/FormElementBase.php b/core/modules/config_translation/src/FormElement/FormElementBase.php
index 86e4c0e..ec9a023 100644
--- a/core/modules/config_translation/src/FormElement/FormElementBase.php
+++ b/core/modules/config_translation/src/FormElement/FormElementBase.php
@@ -23,6 +23,13 @@
   use StringTranslationTrait;
 
   /**
+   * The schema element this form is for.
+   *
+   * @var \Drupal\Core\TypedData\TypedDataInterface
+   */
+  protected $element;
+
+  /**
    * The data definition of the element this form element is for.
    *
    * @var \Drupal\Core\TypedData\DataDefinitionInterface
@@ -32,7 +39,8 @@
   /**
    * Constructs a FormElementBase.
    *
-   * @param TypedDataInterface $element
+   * @param \Drupal\Core\TypedData\TypedDataInterface $element
+   *   The schema element this form element is for.
    */
   public function __construct(TypedDataInterface $element) {
     $this->element = $element;
@@ -62,7 +70,20 @@ public function getElements(LanguageInterface $source_language, LanguageInterfac
   }
 
   /**
-   * {@inheritdoc}
+   * Returns the source element for a given configuration definition.
+   *
+   * This can be either a render array that actually outputs the source values
+   * directly or a read-only form element with the source values depending on
+   * what is considered to provide a more intuitive user interface for the
+   * translator.
+   *
+   * @param \Drupal\Core\Language\LanguageInterface $source_language
+   *   Thee source language of the configuration object.
+   * @param mixed $source_config
+   *   The configuration value of the element in the source language.
+   *
+   * @return array
+   *   A render array for the source value.
    */
   public function getSourceElement(LanguageInterface $source_language, $source_config) {
     if ($source_config) {
@@ -82,9 +103,56 @@ public function getSourceElement(LanguageInterface $source_language, $source_con
     );
   }
 
-
   /**
-   * {@inheritdoc}
+   * Returns the translation form element for a given configuration definition.
+   *
+   * For complex data structures (such as mappings) that are translatable
+   * wholesale but contain non-translatable properties, the form element is
+   * responsible for checking access to the source value of those properties. In
+   * case of formatted text, for example, access to the source text format must
+   * be checked. If the translator does not have access to the text format, the
+   * textarea must be disabled and the translator may not be able to translate
+   * this particular configuration element. If the translator does have access
+   * to the text format, the element must be locked down to that particular text
+   * format; in other words, the format may not be changed by the translator
+   * (because the text format property is not itself translatable).
+   *
+   * In addition, the form element is responsible for checking whether the
+   * value of such non-translatable properties in the translated configuration
+   * is equal to the corresponding source values. If not, that means that the
+   * source value has changed after the translation was added. In this case -
+   * again - the translation of this element must be disabled if the translator
+   * does not have access to the source value of the non-translatable property.
+   * For example, if a formatted text element, whose source format was plain
+   * text when it was first translated, gets changed to the full HTML format,
+   * simply changing the format of the translation would lead to an XSS
+   * vulnerability as the translated text, that was intended to be escaped,
+   * would now be displayed unescaped. Thus, if the translator does not have
+   * access to the Full HTML format, the translation for this particular element
+   * may not be updated at all (the textarea must be disabled). Only if access
+   * to the Full HTML format is granted, an explicit translation taking into
+   * account the updated source value(s) may be submitted.
+   *
+   * In the specific case of formatted text this logic is implemented by
+   * utilizing a form element of type 'text_format' and its #format and
+   * #allowed_formats properties. The access logic explained above is then
+   * handled by the 'text_format' element itself, specifically by
+   * filter_process_format(). In case such a rich element is not available for
+   * translation of complex data, similar access logic must be implemented
+   * manually.
+   *
+   * @param \Drupal\Core\Language\LanguageInterface $language
+   *   The language to display the translation form for.
+   * @param mixed $source_config
+   *   The configuration value of the element in the source language.
+   * @param mixed $translation_config
+   *   The configuration value of the element in the language to translate to.
+   *
+   * @return array
+   *   Form API array to represent the form element.
+   *
+   * @see \Drupal\config_translation\FormElement\TextFormat
+   * @see filter_process_format()
    */
   public function getTranslationElement(LanguageInterface $translation_language, $source_config, $translation_config) {
     // Add basic properties that apply to all form elements.
@@ -101,34 +169,15 @@ public function getTranslationElement(LanguageInterface $translation_language, $
   /**
    * {@inheritdoc}
    */
-  public function setConfig(Config $base_config, LanguageConfigOverride $config_translation, array $config_values, $base_key = NULL) {
-    foreach ($this->element as $key => $element) {
-      if (!isset($config_values[$key])) {
-        continue;
-      }
-      $value = $config_values[$key];
-
-      $element_key = implode('.', array_filter(array($base_key, $key)));
-      $definition = $element->getDataDefinition();
-      // While the 'form_element_class' key is used for form building, the
-      // 'translatable' key is used for the setting of configuration values.
-      // This allows the form to contain values which will not be set, such as
-      // the TextFormat element's 'format' value.
-      if ($element instanceof Element && empty($definition['translatable'])) {
-        // Traverse into this level in the configuration.
-        $this->setConfig($base_config, $config_translation, $value, $element_key);
+  public function setConfig(Config $base_config, LanguageConfigOverride $config_translation, $config_values, $base_key = NULL) {
+      // Save value, if different from the source value in the base
+      // configuration. If same as original configuration, remove override.
+      if ($base_config->get($base_key) !== $config_values) {
+        $config_translation->set($base_key, $config_values);
       }
       else {
-        // Save value, if different from the source value in the base
-        // configuration. If same as original configuration, remove override.
-        if ($base_config->get($element_key) !== $value) {
-          $config_translation->set($element_key, $value);
-        }
-        else {
-          $config_translation->clear($element_key);
-        }
+        $config_translation->clear($base_key);
       }
     }
-  }
 
 }
diff --git a/core/modules/config_translation/src/FormElement/ListElement.php b/core/modules/config_translation/src/FormElement/ListElement.php
index 4230789..0314a3c 100644
--- a/core/modules/config_translation/src/FormElement/ListElement.php
+++ b/core/modules/config_translation/src/FormElement/ListElement.php
@@ -12,6 +12,7 @@
 use Drupal\Core\Language\LanguageInterface;
 use Drupal\Core\Config\Schema\ArrayElement;
 use Drupal\config_translation\Form\ConfigTranslationFormBase;
+use Drupal\Core\TypedData\TypedDataInterface;
 use Drupal\language\Config\LanguageConfigOverride;
 
 /**
@@ -20,6 +21,23 @@
 class ListElement extends FormElementBase {
 
   /**
+   * The schema element this form is for.
+   *
+   * @var \Drupal\Core\Config\Schema\ArrayElement
+   */
+  protected $element;
+
+  /**
+   * Constructs a FormElementBase.
+   *
+   * @param \Drupal\Core\Config\Schema\ArrayElement $element
+   *   The schema element this form element is for.
+   */
+  public function __construct(ArrayElement $element) {
+    parent::__construct($element);
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function getElements(LanguageInterface $source_language, LanguageInterface $translation_language, $source_config, $translation_config, $base_key, $parents) {
@@ -78,14 +96,34 @@ public function getElements(LanguageInterface $source_language, LanguageInterfac
             '#title' => (!empty($title) ? (strip_tags($title) . ' ') : '') . $this->t($definition['label']),
             '#open' => FALSE,
           ) + $sub_build;
-         }
-         else {
-           $build += $sub_build;
-         }
-       }
+        }
+        else {
+          $build += $sub_build;
+        }
+      }
     }
 
     return $build;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function setConfig(Config $base_config, LanguageConfigOverride $config_translation, $config_values, $base_key = NULL) {
+    foreach ($this->element as $key => $element) {
+      // Do not bother traversing schema elements for which no values have been
+      // submitted.
+      if (!isset($config_values[$key])) {
+        continue;
+      }
+      $value = $config_values[$key];
+
+      $element_key = implode('.', array_filter(array($base_key, $key)));
+      if ($form_element = ConfigTranslationFormBase::createFormElement($element)) {
+        // Traverse into the next level of the configuration.
+        $form_element->setConfig($base_config, $config_translation, $value, $element_key);
+      }
+    }
+  }
+
 }
diff --git a/core/modules/config_translation/src/FormElement/TextFormat.php b/core/modules/config_translation/src/FormElement/TextFormat.php
index 1f8f3e7..5948085 100644
--- a/core/modules/config_translation/src/FormElement/TextFormat.php
+++ b/core/modules/config_translation/src/FormElement/TextFormat.php
@@ -37,9 +37,9 @@ public function getTranslationElement(LanguageInterface $translation_language, $
       // Override the #default_value property from the parent class.
       '#default_value' => $translation_config['value'],
       '#format' => $translation_config['format'],
+      // @see \Drupal\config_translation\Element\ElementInterface::getTranslationElement()
       '#allowed_formats' => array($source_config['format']),
     ) + parent::getTranslationElement($translation_language, $source_config, $translation_config);
   }
 
-
 }
diff --git a/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
index f516ca3..6c29709 100644
--- a/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
+++ b/core/modules/config_translation/src/Tests/ConfigTranslationUiTest.php
@@ -100,7 +100,7 @@ protected function setUp() {
   /**
    * Tests the site information translation interface.
    */
-  public function _testSiteInformationTranslationUi() {
+  public function testSiteInformationTranslationUi() {
     $this->drupalLogin($this->admin_user);
 
     $site_name = 'Site name for testing configuration translation';
@@ -166,7 +166,7 @@ public function _testSiteInformationTranslationUi() {
   /**
    * Tests the site information translation interface.
    */
-  public function _testSourceValueDuplicateSave() {
+  public function testSourceValueDuplicateSave() {
     $this->drupalLogin($this->admin_user);
 
     $site_name = 'Site name for testing configuration translation';
@@ -243,7 +243,7 @@ public function _testSourceValueDuplicateSave() {
   /**
    * Tests the contact form translation.
    */
-  public function _testContactConfigEntityTranslation() {
+  public function testContactConfigEntityTranslation() {
     $this->drupalLogin($this->admin_user);
 
     $this->drupalGet('admin/structure/contact');
@@ -374,7 +374,7 @@ public function _testContactConfigEntityTranslation() {
   /**
    * Tests date format translation.
    */
-  public function _testDateFormatTranslation() {
+  public function testDateFormatTranslation() {
     $this->drupalLogin($this->admin_user);
 
     $this->drupalGet('admin/config/regional/date-time');
@@ -439,7 +439,7 @@ public function _testDateFormatTranslation() {
    * names involved building up one configuration translation form. Test that
    * the translations are saved for all configuration names properly.
    */
-  public function _testAccountSettingsConfigurationTranslation() {
+  public function testAccountSettingsConfigurationTranslation() {
     $this->drupalLogin($this->admin_user);
 
     $this->drupalGet('admin/config/people/accounts/translate');
@@ -469,7 +469,7 @@ public function _testAccountSettingsConfigurationTranslation() {
   /**
    * Tests source and target language edge cases.
    */
-  public function _testSourceAndTargetLanguage() {
+  public function testSourceAndTargetLanguage() {
     $this->drupalLogin($this->admin_user);
 
     // Loading translation page for not-specified language (und)
@@ -517,7 +517,7 @@ public function _testSourceAndTargetLanguage() {
   /**
    * Tests the views translation interface.
    */
-  public function _testViewsTranslationUI() {
+  public function testViewsTranslationUI() {
     $this->drupalLogin($this->admin_user);
 
     // Assert contextual link related to views.
@@ -569,7 +569,7 @@ public function _testViewsTranslationUI() {
   /**
    * Test translation storage in locale storage.
    */
-  public function _testLocaleDBStorage() {
+  public function testLocaleDBStorage() {
     // Enable import of translations. By default this is disabled for automated
     // tests.
     \Drupal::config('locale.settings')
@@ -617,7 +617,7 @@ public function _testLocaleDBStorage() {
   /**
    * Tests the single language existing.
    */
-  public function _testSingleLanguageUI() {
+  public function testSingleLanguageUI() {
     $this->drupalLogin($this->admin_user);
 
     // Delete French language
@@ -644,7 +644,7 @@ public function _testSingleLanguageUI() {
   /**
    * Tests the config_translation_info_alter() hook.
    */
-  public function _testAlterInfo() {
+  public function testAlterInfo() {
     $this->drupalLogin($this->admin_user);
 
     $this->container->get('state')->set('config_translation_test_config_translation_info_alter', TRUE);
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config/install/config_translation_test.content.yml b/core/modules/config_translation/tests/modules/config_translation_test/config/install/config_translation_test.content.yml
index 55aa430..5a4d4bb 100644
--- a/core/modules/config_translation/tests/modules/config_translation_test/config/install/config_translation_test.content.yml
+++ b/core/modules/config_translation/tests/modules/config_translation_test/config/install/config_translation_test.content.yml
@@ -2,5 +2,5 @@ id: test
 label: 'Test'
 langcode: en
 content:
-  value: "<strong>Hello World</strong>"
+  value: "<p><strong>Hello World</strong></p>"
   format: plain_text
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.links.task.yml b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.links.task.yml
new file mode 100644
index 0000000..92581b4
--- /dev/null
+++ b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.links.task.yml
@@ -0,0 +1,7 @@
+# Add a default local task for the file system settings page, so that the local
+# task added by Configuration Translation becomes visible. This facilitates
+# manual testing.
+system.file_system_settings:
+  route_name: system.file_system_settings
+  title: Settings
+  base_route: system.file_system_settings
diff --git a/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.local_tasks.yml b/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.local_tasks.yml
deleted file mode 100644
index 92581b4..0000000
--- a/core/modules/config_translation/tests/modules/config_translation_test/config_translation_test.local_tasks.yml
+++ /dev/null
@@ -1,7 +0,0 @@
-# Add a default local task for the file system settings page, so that the local
-# task added by Configuration Translation becomes visible. This facilitates
-# manual testing.
-system.file_system_settings:
-  route_name: system.file_system_settings
-  title: Settings
-  base_route: system.file_system_settings