diff --git a/core/lib/Drupal/Core/Config/ConfigFactory.php b/core/lib/Drupal/Core/Config/ConfigFactory.php
index cf3688d..0c4322c 100644
--- a/core/lib/Drupal/Core/Config/ConfigFactory.php
+++ b/core/lib/Drupal/Core/Config/ConfigFactory.php
@@ -75,7 +75,13 @@ class ConfigFactory implements ConfigFactoryInterface, EventSubscriberInterface
    *
    * @var array
    */
-  protected $cannotOverridable = ['core.extension'];
+  protected $cannotOverride = [
+    // Due to side effects of doing a module install or uninstall.
+    'core.extension',
+    // Due to the fact that this information is cached in a way that is not
+    // config override aware.
+    'menu_link.static.overrides'
+  ];
 
   /**
    * Constructs the Config factory.
@@ -404,6 +410,6 @@ protected function createConfigObject($name, $immutable) {
    *   Returns TRUE if the configuration object can be overridden.
    */
   protected function canOverride($name) {
-    return !in_array($name, $this->cannotOverridable);
+    return !in_array($name, $this->cannotOverride);
   }
 }
diff --git a/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php b/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php
index 0204a1f..c3024b0 100644
--- a/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php
+++ b/core/lib/Drupal/Core/Form/ConfigFormBaseTrait.php
@@ -12,11 +12,18 @@
 /**
  * Provides access to configuration for forms.
  *
+ * This trait provides a config() method that returns override free and mutable
+ * config objects if the configuration name is in the array returned by the
+ * getEditableConfigNames() implementation.
+ *
  * Forms that present configuration to the user have to take care not to save
  * configuration overrides to the stored configuration since overrides are often
- * environment specific. This trait provides a config() method that returns
- * override free and mutable config objects if the configuration name is in the
- * array returned by the getEditableConfigNames() implementation.
+ * environment specific. Default values of form elements should be obtained from
+ * override free configuration objects. However, if a form reacts to
+ * configuration in anyway, for example sends an email to the system.site:mail
+ * address, then it is important that the value comes from a configuration
+ * object with overrides. Therefore, override free and editable configuration
+ * objects are limited to those listed by the getEditableConfigNames() method.
  */
 trait ConfigFormBaseTrait {
 
diff --git a/core/lib/Drupal/Core/Menu/StaticMenuLinkOverrides.php b/core/lib/Drupal/Core/Menu/StaticMenuLinkOverrides.php
index 01fbb65..659ff90 100644
--- a/core/lib/Drupal/Core/Menu/StaticMenuLinkOverrides.php
+++ b/core/lib/Drupal/Core/Menu/StaticMenuLinkOverrides.php
@@ -17,6 +17,10 @@ class StaticMenuLinkOverrides implements StaticMenuLinkOverridesInterface {
   /**
    * The config name used to store the overrides.
    *
+   * This configuration can not be overridden by configuration overrides because
+   * menu links and these overrides are cached in a way that is not override
+   * aware.
+   *
    * @var string
    */
   protected $configName = 'menu_link.static.overrides';
@@ -54,6 +58,7 @@ public function __construct(ConfigFactoryInterface $config_factory) {
    */
   protected function getConfig() {
     if (empty($this->config)) {
+      // Get an override free and editable configuration object.
       $this->config = $this->configFactory->getEditable($this->configName);
     }
     return $this->config;
@@ -80,7 +85,7 @@ public function loadOverride($id) {
    * {@inheritdoc}
    */
   public function deleteMultipleOverrides(array $ids) {
-    $all_overrides = $this->getConfig()->getOriginal('definitions', FALSE);
+    $all_overrides = $this->getConfig()->get('definitions');
     $save = FALSE;
     foreach ($ids as $id) {
       $id = static::encodeId($id);
@@ -135,7 +140,7 @@ public function saveOverride($id, array $definition) {
     $definition = array_intersect_key($definition, $expected);
     if ($definition) {
       $id = static::encodeId($id);
-      $all_overrides = $this->getConfig()->getOriginal('definitions', FALSE);
+      $all_overrides = $this->getConfig()->get('definitions', FALSE);
       // Combine with any existing data.
       $all_overrides[$id] = $definition + $this->loadOverride($id);
       $this->getConfig()->set('definitions', $all_overrides)->save();
diff --git a/core/modules/aggregator/src/Plugin/AggregatorPluginSettingsBase.php b/core/modules/aggregator/src/Plugin/AggregatorPluginSettingsBase.php
index 15e3c3d..eb6ad36 100644
--- a/core/modules/aggregator/src/Plugin/AggregatorPluginSettingsBase.php
+++ b/core/modules/aggregator/src/Plugin/AggregatorPluginSettingsBase.php
@@ -8,8 +8,6 @@
 namespace Drupal\aggregator\Plugin;
 
 use Drupal\Component\Plugin\ConfigurablePluginInterface;
-use Drupal\Core\Config\ConfigFactoryInterface;
-use Drupal\Core\Form\ConfigFormBaseTrait;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\PluginBase;
 use Drupal\Core\Plugin\PluginFormInterface;
@@ -27,29 +25,6 @@
  * @see plugin_api
  */
 abstract class AggregatorPluginSettingsBase extends PluginBase implements PluginFormInterface, ConfigurablePluginInterface {
-  use ConfigFormBaseTrait;
-
-  /**
-   * Contains the configuration object factory.
-   *
-   * @var \Drupal\Core\Config\ConfigFactoryInterface
-   */
-  protected $configFactory;
-
-  /**
-   * Constructs a Drupal\Component\Plugin\PluginBase object.
-   *
-   * @param array $configuration
-   *   A configuration array containing information about the plugin instance.
-   * @param string $plugin_id
-   *   The plugin_id for the plugin instance.
-   * @param mixed $plugin_definition
-   *   The plugin implementation definition.
-   */
-  public function __construct(array $configuration, $plugin_id, $plugin_definition, ConfigFactoryInterface $config_factory) {
-    parent::__construct($configuration, $plugin_id, $plugin_definition);
-    $this->configFactory = $config_factory;
-  }
 
   /**
    * {@inheritdoc}
diff --git a/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php b/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php
index 8290527..f51a403 100644
--- a/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php
+++ b/core/modules/aggregator/src/Plugin/aggregator/processor/DefaultProcessor.php
@@ -16,6 +16,7 @@
 use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Datetime\DateFormatter;
 use Drupal\Core\Entity\Query\QueryInterface;
+use Drupal\Core\Form\ConfigFormBaseTrait;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Routing\UrlGeneratorTrait;
@@ -33,7 +34,7 @@
  * )
  */
 class DefaultProcessor extends AggregatorPluginSettingsBase implements ProcessorInterface, ContainerFactoryPluginInterface {
-
+  use ConfigFormBaseTrait;
   use UrlGeneratorTrait;
 
   /**
@@ -83,13 +84,13 @@ class DefaultProcessor extends AggregatorPluginSettingsBase implements Processor
    *   The date formatter service.
    */
   public function __construct(array $configuration, $plugin_id, $plugin_definition, ConfigFactoryInterface $config, QueryInterface $item_query, ItemStorageInterface $item_storage, DateFormatter $date_formatter) {
+    $this->configFactory = $config;
     $this->itemStorage = $item_storage;
     $this->itemQuery = $item_query;
     $this->dateFormatter = $date_formatter;
-    $this->configFactory = $config;
     // @todo Refactor aggregator plugins to ConfigEntity so merging
     //   the configuration here is not needed.
-    parent::__construct($configuration + $this->getConfiguration(), $plugin_id, $plugin_definition, $config);
+    parent::__construct($configuration + $this->getConfiguration(), $plugin_id, $plugin_definition);
   }
 
   /**
diff --git a/core/modules/aggregator/tests/modules/aggregator_test/src/Plugin/aggregator/processor/TestProcessor.php b/core/modules/aggregator/tests/modules/aggregator_test/src/Plugin/aggregator/processor/TestProcessor.php
index 6e08844..1a6ee19 100644
--- a/core/modules/aggregator/tests/modules/aggregator_test/src/Plugin/aggregator/processor/TestProcessor.php
+++ b/core/modules/aggregator/tests/modules/aggregator_test/src/Plugin/aggregator/processor/TestProcessor.php
@@ -11,6 +11,7 @@
 use Drupal\aggregator\Plugin\ProcessorInterface;
 use Drupal\aggregator\FeedInterface;
 use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Form\ConfigFormBaseTrait;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -27,6 +28,14 @@
  * )
  */
 class TestProcessor extends AggregatorPluginSettingsBase implements ProcessorInterface, ContainerFactoryPluginInterface {
+  use ConfigFormBaseTrait;
+
+  /**
+   * Contains the configuration object factory.
+   *
+   * @var \Drupal\Core\Config\ConfigFactoryInterface
+   */
+  protected $configFactory;
 
   /**
    * {@inheritdoc}
@@ -54,7 +63,7 @@ public static function create(ContainerInterface $container, array $configuratio
    */
   public function __construct(array $configuration, $plugin_id, $plugin_definition, ConfigFactoryInterface $config) {
     $this->configFactory = $config;
-    parent::__construct($configuration + $this->getConfiguration(), $plugin_id, $plugin_definition, $config);
+    parent::__construct($configuration + $this->getConfiguration(), $plugin_id, $plugin_definition);
   }
 
   /**
diff --git a/core/modules/book/book.module b/core/modules/book/book.module
index f55c472..57ee1ab 100644
--- a/core/modules/book/book.module
+++ b/core/modules/book/book.module
@@ -561,7 +561,7 @@ function book_node_type_update(NodeTypeInterface $type) {
   if ($type->getOriginalId() != $type->id()) {
     $config = \Drupal::configFactory()->getEditable('book.settings');
     // Update the list of node types that are allowed to be added to books.
-    $allowed_types = $config->getOriginal('allowed_types', FALSE);
+    $allowed_types = $config->get('allowed_types');
     $old_key = array_search($type->getOriginalId(), $allowed_types);
 
     if ($old_key !== FALSE) {
@@ -573,7 +573,7 @@ function book_node_type_update(NodeTypeInterface $type) {
     }
 
     // Update the setting for the "Add child page" link.
-    if ($config->getOriginal('child_type', FALSE) == $type->getOriginalId()) {
+    if ($config->get('child_type') == $type->getOriginalId()) {
       $config->set('child_type', $type->id());
     }
     $config->save();
diff --git a/core/modules/color/color.module b/core/modules/color/color.module
index 71f5d82..7d8473c 100644
--- a/core/modules/color/color.module
+++ b/core/modules/color/color.module
@@ -169,7 +169,9 @@ function color_get_palette($theme, $default = FALSE) {
 
   // Load variable.
   // @todo Default color config should be moved to yaml in the theme.
-  return \Drupal::config('color.theme.' . $theme)->get('palette') ?: $palette;
+  // Getting a mutable override-free object because overriding color
+  // configuration makes no sense.
+  return \Drupal::configFactory()->getEditable('color.theme.' . $theme)->get('palette') ?: $palette;
 }
 
 /**
@@ -199,7 +201,9 @@ function color_scheme_form($complete_form, FormStateInterface $form_state, $them
   // Note: we use configuration without overrides since this information is used
   // in a form and therefore without doing this would bleed overrides into
   // active configuration.
-  $current_scheme = \Drupal::config('color.theme.' . $theme)->getOriginal('palette', FALSE);
+  // Getting a mutable override-free object because overriding color
+  // configuration makes no sense.
+  $current_scheme = \Drupal::configFactory()->getEditable('color.theme.' . $theme)->get('palette');
   foreach ($schemes as $key => $scheme) {
     if ($current_scheme == $scheme) {
       $scheme_name = $key;
@@ -624,7 +628,7 @@ function _color_render_images($theme, &$info, &$paths, $palette) {
     if ($file == 'screenshot.png') {
       $slice = imagecreatetruecolor(150, 90);
       imagecopyresampled($slice, $target, 0, 0, $x, $y, 150, 90, $width, $height);
-      \Drupal::config('color.theme.' . $theme)
+      \Drupal::configFactory()->getEditable('color.theme.' . $theme)
         ->set('screenshot', $image)
         ->save();
     }
diff --git a/core/modules/config/src/Form/ConfigSingleImportForm.php b/core/modules/config/src/Form/ConfigSingleImportForm.php
index 3ef3d33..ee1dfde 100644
--- a/core/modules/config/src/Form/ConfigSingleImportForm.php
+++ b/core/modules/config/src/Form/ConfigSingleImportForm.php
@@ -8,7 +8,6 @@
 namespace Drupal\config\Form;
 
 use Drupal\Component\Serialization\Yaml;
-use Drupal\Core\Config\ConfigFactoryInterface;
 use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Form\ConfirmFormBase;
@@ -56,13 +55,10 @@ class ConfigSingleImportForm extends ConfirmFormBase {
    *   The entity manager.
    * @param \Drupal\Core\Config\StorageInterface $config_storage
    *   The config storage.
-   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
-   *   The config factory.
    */
-  public function __construct(EntityManagerInterface $entity_manager, StorageInterface $config_storage, ConfigFactoryInterface $config_factory) {
+  public function __construct(EntityManagerInterface $entity_manager, StorageInterface $config_storage) {
     $this->entityManager = $entity_manager;
     $this->configStorage = $config_storage;
-    $this->configFactory = $config_factory;
   }
 
   /**
@@ -71,8 +67,7 @@ public function __construct(EntityManagerInterface $entity_manager, StorageInter
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('entity.manager'),
-      $container->get('config.storage'),
-      $container->get('config.factory')
+      $container->get('config.storage')
     );
   }
 
@@ -248,7 +243,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
 
     // If a simple configuration file was added, set the data and save.
     if ($this->data['config_type'] === 'system.simple') {
-      $this->configFactory->getEditable($this->data['config_name'])->setData($this->data['import'])->save();
+      $this->configFactory()->getEditable($this->data['config_name'])->setData($this->data['import'])->save();
       drupal_set_message($this->t('The %name configuration was imported.', array('%name' => $this->data['config_name'])));
     }
     // For a config entity, create an entity and save it.
diff --git a/core/modules/contact/contact.module b/core/modules/contact/contact.module
index 33eb25a..6764e81 100644
--- a/core/modules/contact/contact.module
+++ b/core/modules/contact/contact.module
@@ -194,7 +194,6 @@ function contact_form_user_admin_settings_alter(&$form, FormStateInterface $form
     '#type' => 'checkbox',
     '#title' => t('Enable the personal contact form by default for new users'),
     '#description' => t('Changing this setting will not affect existing users.'),
-    // @see \Drupal\Core\Form\ConfigFormBase::config()
     '#default_value' => \Drupal::configFactory()->getEditable('contact.settings')->get('user_default_enabled'),
   );
   // Add submit handler to save contact configuration.
diff --git a/core/modules/contact/src/ContactFormEditForm.php b/core/modules/contact/src/ContactFormEditForm.php
index 520f5b0..420be7d 100644
--- a/core/modules/contact/src/ContactFormEditForm.php
+++ b/core/modules/contact/src/ContactFormEditForm.php
@@ -21,24 +21,6 @@ class ContactFormEditForm extends EntityForm {
   use ConfigFormBaseTrait;
 
   /**
-   * Constructs the ContactFormEditForm.
-   *
-   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
-   *   The config factory.
-   */
-  public function __construct(ConfigFactoryInterface $config_factory) {
-    $this->configFactory = $config_factory;
-  }
-  /**
-   * {@inheritdoc}
-   */
-  public static function create(ContainerInterface $container) {
-    return new static(
-      $container->get('config.factory')
-    );
-  }
-
-  /**
    * {@inheritdoc}
    */
   protected function getEditableConfigNames() {
diff --git a/core/modules/language/language.module b/core/modules/language/language.module
index 69f1ba4..358dd4a 100644
--- a/core/modules/language/language.module
+++ b/core/modules/language/language.module
@@ -339,7 +339,8 @@ function language_negotiation_url_prefixes_update() {
  * Saves language prefix settings.
  */
 function language_negotiation_url_prefixes_save(array $prefixes) {
-  // @fixme this is super dodgy - overrides can bleed.
+  // @todo https://www.drupal.org/node/2403229 $prefixes can contain
+  //   configuration overrides.
   \Drupal::configFactory()->getEditable('language.negotiation')
   ->set('url.prefixes', $prefixes)
   ->save();
@@ -356,7 +357,8 @@ function language_negotiation_url_domains() {
  * Saves the language domain settings.
  */
 function language_negotiation_url_domains_save(array $domains) {
-  // @fixme this is super dodgy - overrides can bleed.
+  // @todo https://www.drupal.org/node/2403229 $domains can contain
+  //   configuration overrides.
   \Drupal::configFactory()->getEditable('language.negotiation')
   ->set('url.domains', $domains)
   ->save();
@@ -494,8 +496,6 @@ function language_form_alter(&$form, FormStateInterface $form_state) {
  * @see language_form_system_regional_settings_alter()
  */
 function language_system_regional_settings_form_submit($form, FormStateInterface $form_state) {
-  // @fixme can config overrides bleed here? Default language is injected into
-  //   the container.
   \Drupal::configFactory()->getEditable('system.site')->set('langcode', $form_state->getValue('site_default_language'))->save();
 }
 
diff --git a/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php b/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php
index 8276d95..5e511b6 100644
--- a/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php
+++ b/core/modules/language/src/Form/NegotiationBrowserDeleteForm.php
@@ -27,25 +27,6 @@ class NegotiationBrowserDeleteForm extends ConfirmFormBase {
   protected $browserLangcode;
 
   /**
-   * Constructs the NegotiationBrowserDeleteForm object.
-   *
-   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
-   *   The config factory.
-   */
-  public function __construct(ConfigFactoryInterface $config_factory) {
-    $this->configFactory = $config_factory;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function create(ContainerInterface $container) {
-    return new static(
-      $container->get('config.factory')
-    );
-  }
-
-  /**
    * {@inheritdoc}
    */
   public function getQuestion() {
@@ -85,7 +66,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
 
     if (array_key_exists($this->browserLangcode, $mappings)) {
       unset($mappings[$this->browserLangcode]);
-      $this->configFactory->getEditable('language.mappings')
+      $this->configFactory()->getEditable('language.mappings')
         ->clear($this->browserLangcode)
         ->save();
 
diff --git a/core/modules/locale/locale.module b/core/modules/locale/locale.module
index 8665e48..79b2a50 100644
--- a/core/modules/locale/locale.module
+++ b/core/modules/locale/locale.module
@@ -647,7 +647,7 @@ function locale_form_language_admin_edit_form_alter(&$form, FormStateInterface $
     $form['locale_translate_english'] = array(
       '#title' => t('Enable interface translation to English'),
       '#type' => 'checkbox',
-      '#default_value' => \Drupal::config('locale.settings')->getOriginal('translate_english', FALSE),
+      '#default_value' => \Drupal::configFactory()->getEditable('locale.settings')->get('translate_english'),
     );
     $form['actions']['submit']['#submit'][] = 'locale_form_language_admin_edit_form_alter_submit';
   }
diff --git a/core/tests/Drupal/Tests/Core/Menu/StaticMenuLinkOverridesTest.php b/core/tests/Drupal/Tests/Core/Menu/StaticMenuLinkOverridesTest.php
index 590bd21..6c55354 100644
--- a/core/tests/Drupal/Tests/Core/Menu/StaticMenuLinkOverridesTest.php
+++ b/core/tests/Drupal/Tests/Core/Menu/StaticMenuLinkOverridesTest.php
@@ -15,11 +15,6 @@
  * @group Menu
  */
 class StaticMenuLinkOverridesTest extends UnitTestCase {
-  protected function setUp() {
-    $this->markTestSkipped('Crazy test');
-    parent::setUp(); // TODO: Change the autogenerated stub
-  }
-
 
   /**
    * Tests the constructor.
@@ -107,7 +102,6 @@ public function testLoadMultipleOverrides() {
    * @covers ::getConfig
    */
   public function testSaveOverride() {
-    $this->markTestSkipped('Crazy test');
     $config = $this->getMockBuilder('Drupal\Core\Config\Config')
       ->disableOriginalConstructor()
       ->getMock();
@@ -150,7 +144,7 @@ public function testSaveOverride() {
 
     $config_factory = $this->getMock('Drupal\Core\Config\ConfigFactoryInterface');
     $config_factory->expects($this->once())
-      ->method('get')
+      ->method('getEditable')
       ->will($this->returnValue($config));
 
     $static_override = new StaticMenuLinkOverrides($config_factory);
@@ -172,7 +166,6 @@ public function testSaveOverride() {
    * @dataProvider providerTestDeleteOverrides
    */
   public function testDeleteOverrides($ids, array $old_definitions, array $new_definitions) {
-    $this->markTestSkipped('Crazy test');
     $config = $this->getMockBuilder('Drupal\Core\Config\Config')
       ->disableOriginalConstructor()
       ->getMock();
@@ -193,7 +186,7 @@ public function testDeleteOverrides($ids, array $old_definitions, array $new_def
 
     $config_factory = $this->getMock('Drupal\Core\Config\ConfigFactoryInterface');
     $config_factory->expects($this->once())
-      ->method('get')
+      ->method('getEditable')
       ->will($this->returnValue($config));
 
     $static_override = new StaticMenuLinkOverrides($config_factory);