diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index 5a8d4ff..f91b8a9 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -89,7 +89,7 @@ public function get($property_name, $langcode = NULL) {
    * EntityInterface::set() implements support for fieldable entities, but
    * configuration entities are not fieldable.
    */
-  public function set($property_name, $value, $langcode = NULL) {
+  public function set($property_name, $value, $langcode = NULL, $notify = TRUE) {
     // @todo: Add support for translatable properties being not fields.
     $this->{$property_name} = $value;
   }
diff --git a/core/lib/Drupal/Core/Config/Schema/Mapping.php b/core/lib/Drupal/Core/Config/Schema/Mapping.php
index e958f07..b7bddb3 100644
--- a/core/lib/Drupal/Core/Config/Schema/Mapping.php
+++ b/core/lib/Drupal/Core/Config/Schema/Mapping.php
@@ -52,7 +52,11 @@ public function get($property_name) {
   /**
    * Implements Drupal\Core\TypedData\ComplexDataInterface::set().
    */
-  public function set($property_name, $value) {
+  public function set($property_name, $value, $notify = TRUE) {
+    // Notify the parent of any changes to be made.
+    if ($notify && isset($this->parent)) {
+      $this->parent->onChange($this->name);
+    }
     // Set the data into the configuration array but behave according to the
     // interface specification when we've got a null value.
     if (isset($value)) {
diff --git a/core/lib/Drupal/Core/Entity/Entity.php b/core/lib/Drupal/Core/Entity/Entity.php
index 11934bf..c2f9d3a 100644
--- a/core/lib/Drupal/Core/Entity/Entity.php
+++ b/core/lib/Drupal/Core/Entity/Entity.php
@@ -191,7 +191,7 @@ public function get($property_name, $langcode = NULL) {
   /**
    * Implements \Drupal\Core\TypedData\ComplexDataInterface::set().
    */
-  public function set($property_name, $value) {
+  public function set($property_name, $value, $notify = TRUE) {
     // @todo: Replace by EntityNG implementation once all entity types have been
     // converted to use the entity field API.
     $this->{$property_name} = $value;
diff --git a/core/lib/Drupal/Core/Entity/EntityBCDecorator.php b/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
index 481f01a..95bd85d 100644
--- a/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
+++ b/core/lib/Drupal/Core/Entity/EntityBCDecorator.php
@@ -229,7 +229,7 @@ public function get($property_name) {
   /**
    * Forwards the call to the decorated entity.
    */
-  public function set($property_name, $value) {
+  public function set($property_name, $value, $notify = TRUE) {
     // Ensure this works with not yet defined fields.
     if (!isset($this->definitions[$property_name])) {
       return $this->__set($property_name, $value);
diff --git a/core/lib/Drupal/Core/Entity/EntityNG.php b/core/lib/Drupal/Core/Entity/EntityNG.php
index 14403bb..9406927 100644
--- a/core/lib/Drupal/Core/Entity/EntityNG.php
+++ b/core/lib/Drupal/Core/Entity/EntityNG.php
@@ -179,8 +179,8 @@ protected function getTranslatedField($property_name, $langcode) {
   /**
    * Implements \Drupal\Core\TypedData\ComplexDataInterface::set().
    */
-  public function set($property_name, $value) {
-    $this->get($property_name)->setValue($value);
+  public function set($property_name, $value, $notify = TRUE) {
+    $this->get($property_name)->setValue($value, FALSE);
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php b/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php
index 01966c7..1ea77ee 100644
--- a/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php
+++ b/core/lib/Drupal/Core/Entity/Field/FieldItemBase.php
@@ -80,15 +80,15 @@ public function __get($name) {
   /**
    * Overrides \Drupal\Core\TypedData\Type\Map::set().
    */
-  public function set($property_name, $value) {
+  public function set($property_name, $value, $notify = TRUE) {
+    // Notify the parent of any changes to be made.
+    if ($notify && isset($this->parent)) {
+      $this->parent->onChange($this->name);
+    }
     if (isset($this->properties[$property_name])) {
-      $this->properties[$property_name]->setValue($value);
+      $this->properties[$property_name]->setValue($value, FALSE);
     }
     else {
-      // Notify the parent of any changes to be made.
-      if (isset($this->parent)) {
-        $this->parent->onChange($this->name);
-      }
       // Just set the plain value, which allows adding a new entry to the map.
       $this->values[$property_name] = $value;
     }
diff --git a/core/lib/Drupal/Core/Entity/Field/Type/EntityReferenceItem.php b/core/lib/Drupal/Core/Entity/Field/Type/EntityReferenceItem.php
index 17a57da..5b78a05 100644
--- a/core/lib/Drupal/Core/Entity/Field/Type/EntityReferenceItem.php
+++ b/core/lib/Drupal/Core/Entity/Field/Type/EntityReferenceItem.php
@@ -87,11 +87,10 @@ public function __isset($property_name) {
    * Overrides \Drupal\Core\Entity\Field\FieldItemBase::get().
    */
   public function setValue($values, $notify = TRUE) {
-    // Treat the values as property value of the first property, if no array is
+    // Treat the values as property value of the entity property, if no array is
     // given.
     if (isset($values) && !is_array($values)) {
-      $keys = array_keys($this->getPropertyDefinitions());
-      $values = array($keys[0] => $values);
+      $values = array('entity' => $values);
     }
     // Make sure that the 'entity' property gets set as 'target_id'.
     if (isset($values['target_id']) && !isset($values['entity'])) {
diff --git a/core/lib/Drupal/Core/Entity/Field/Type/EntityTranslation.php b/core/lib/Drupal/Core/Entity/Field/Type/EntityTranslation.php
index 4765a54..84293c3 100644
--- a/core/lib/Drupal/Core/Entity/Field/Type/EntityTranslation.php
+++ b/core/lib/Drupal/Core/Entity/Field/Type/EntityTranslation.php
@@ -105,8 +105,8 @@ public function get($property_name) {
   /**
    * Implements \Drupal\Core\TypedData\ComplexDataInterface::set().
    */
-  public function set($property_name, $value) {
-    $this->get($property_name)->setValue($value);
+  public function set($property_name, $value, $notify = TRUE) {
+    $this->get($property_name)->setValue($value, FALSE);
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php b/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php
index 92fab01..dad6a57 100644
--- a/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php
+++ b/core/lib/Drupal/Core/Entity/Field/Type/EntityWrapper.php
@@ -102,11 +102,7 @@ public function setValue($value, $notify = TRUE) {
     }
     // Update the 'id source' property, if given.
     if (!empty($this->definition['settings']['id source'])) {
-      // We only need to update the source, if we are not invoked from the
-      // parent, i.e. when notify is TRUE.
-      if ($notify) {
-        $this->parent->__set($this->definition['settings']['id source'], $value);
-      }
+      $this->parent->__set($this->definition['settings']['id source'], $value, $notify);
     }
     else {
       // Notify the parent of any changes to be made.
@@ -150,8 +146,8 @@ public function get($property_name) {
   /**
    * Implements \Drupal\Core\TypedData\ComplexDataInterface::set().
    */
-  public function set($property_name, $value) {
-    $this->get($property_name)->setValue($value);
+  public function set($property_name, $value, $notify = TRUE) {
+    $this->get($property_name)->setValue($value, FALSE);
   }
 
   /**
diff --git a/core/lib/Drupal/Core/Entity/Field/Type/LanguageItem.php b/core/lib/Drupal/Core/Entity/Field/Type/LanguageItem.php
index 613f525..2db12e1 100644
--- a/core/lib/Drupal/Core/Entity/Field/Type/LanguageItem.php
+++ b/core/lib/Drupal/Core/Entity/Field/Type/LanguageItem.php
@@ -50,11 +50,10 @@ public function getPropertyDefinitions() {
    * Overrides \Drupal\Core\Entity\Field\FieldItemBase::get().
    */
   public function setValue($values, $notify = TRUE) {
-    // Treat the values as property value of the first property, if no array is
-    // given.
+    // Treat the values as property value of the language property, if no array
+    // is given.
     if (isset($values) && !is_array($values)) {
-      $keys = array_keys($this->getPropertyDefinitions());
-      $values = array($keys[0] => $values);
+      $values = array('language' => $values);
     }
     // Make sure that the 'language' property gets set as 'value'.
     if (isset($values['value']) && !isset($values['language'])) {
diff --git a/core/lib/Drupal/Core/TypedData/ComplexDataInterface.php b/core/lib/Drupal/Core/TypedData/ComplexDataInterface.php
index e3a540b..595064e 100644
--- a/core/lib/Drupal/Core/TypedData/ComplexDataInterface.php
+++ b/core/lib/Drupal/Core/TypedData/ComplexDataInterface.php
@@ -44,6 +44,10 @@ public function get($property_name);
    *   The name of the property to set; e.g., 'title' or 'name'.
    * @param $value
    *   The value to set, or NULL to unset the property.
+   * @param bool $notify
+   *   (optional) Whether to notify the parent object of the change. Defaults to
+   *   TRUE. If the update stems from a parent object, set it to FALSE to avoid
+   *   being notified again.
    *
    * @throws \InvalidArgumentException
    *   If the specified property does not exist.
@@ -51,7 +55,7 @@ public function get($property_name);
    * @return \Drupal\Core\TypedData\TypedDataInterface
    *   The property object.
    */
-  public function set($property_name, $value);
+  public function set($property_name, $value, $notify = TRUE);
 
   /**
    * Gets an array of property objects.
diff --git a/core/lib/Drupal/Core/TypedData/Type/Language.php b/core/lib/Drupal/Core/TypedData/Type/Language.php
index 1b72584..b910216 100644
--- a/core/lib/Drupal/Core/TypedData/Type/Language.php
+++ b/core/lib/Drupal/Core/TypedData/Type/Language.php
@@ -62,11 +62,7 @@ public function setValue($value, $notify = TRUE) {
     }
     // Update the 'langcode source' property, if given.
     if (!empty($this->definition['settings']['langcode source'])) {
-      // We only need to update the source, if we are not invoked from the
-      // parent, i.e. when notify is TRUE.
-      if ($notify) {
-        $this->parent->__set($this->definition['settings']['langcode source'], $value);
-      }
+      $this->parent->__set($this->definition['settings']['langcode source'], $value, $notify);
     }
     else {
       // Notify the parent of any changes to be made.
diff --git a/core/lib/Drupal/Core/TypedData/Type/Map.php b/core/lib/Drupal/Core/TypedData/Type/Map.php
index 338ff8e..da20e96 100644
--- a/core/lib/Drupal/Core/TypedData/Type/Map.php
+++ b/core/lib/Drupal/Core/TypedData/Type/Map.php
@@ -124,7 +124,11 @@ public function get($property_name) {
   /**
    * Implements \Drupal\Core\TypedData\ComplexDataInterface::set().
    */
-  public function set($property_name, $value) {
+  public function set($property_name, $value, $notify = TRUE) {
+    // Notify the parent of any changes to be made.
+    if ($notify && isset($this->parent)) {
+      $this->parent->onChange($this->name);
+    }
     if ($this->getPropertyDefinition($property_name)) {
       $this->get($property_name)->setValue($value);
     }
diff --git a/core/lib/Drupal/Core/TypedData/TypedDataInterface.php b/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
index e598f9f..dc313e3 100644
--- a/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
+++ b/core/lib/Drupal/Core/TypedData/TypedDataInterface.php
@@ -43,7 +43,7 @@ public function getValue();
    * @param mixed|null $value
    *   The value to set in the format as documented for the data type or NULL to
    *   unset the data value.
-   * @param bool
+   * @param bool $notify
    *   (optional) Whether to notify the parent object of the change. Defaults to
    *   TRUE. If a property is updated from a parent object, set it to FALSE to
    *   avoid being notified again.
diff --git a/core/modules/file/lib/Drupal/file/Type/FileItem.php b/core/modules/file/lib/Drupal/file/Type/FileItem.php
index 64815fe..0b2c74b 100644
--- a/core/modules/file/lib/Drupal/file/Type/FileItem.php
+++ b/core/modules/file/lib/Drupal/file/Type/FileItem.php
@@ -61,11 +61,10 @@ public function getPropertyDefinitions() {
    * Overrides \Drupal\Core\Entity\Field\FieldItemBase::get().
    */
   public function setValue($values, $notify = TRUE) {
-    // Treat the values as property value of the first property, if no array is
+    // Treat the values as property value of the entity property, if no array is
     // given.
     if (isset($values) && !is_array($values)) {
-      $keys = array_keys($this->getPropertyDefinitions());
-      $values = array($keys[0] => $values);
+      $values = array('entity' => $values);
     }
     // Make sure that the 'entity' property gets set as 'fid'.
     if (isset($values['fid']) && !isset($values['entity'])) {
diff --git a/core/modules/image/lib/Drupal/image/Type/ImageItem.php b/core/modules/image/lib/Drupal/image/Type/ImageItem.php
index 03d48c9..f6cedf2 100644
--- a/core/modules/image/lib/Drupal/image/Type/ImageItem.php
+++ b/core/modules/image/lib/Drupal/image/Type/ImageItem.php
@@ -68,11 +68,10 @@ public function getPropertyDefinitions() {
    * Overrides \Drupal\Core\Entity\Field\FieldItemBase::get().
    */
   public function setValue($values, $notify = TRUE) {
-    // Treat the values as property value of the first property, if no array is
+    // Treat the values as property value of the entity property, if no array is
     // given.
     if (isset($values) && !is_array($values)) {
-      $keys = array_keys($this->getPropertyDefinitions());
-      $values = array($keys[0] => $values);
+      $values = array('entity' => $values);
     }
     // Make sure that the 'entity' property gets set as 'fid'.
     if (isset($values['fid']) && !isset($values['entity'])) {
diff --git a/core/modules/taxonomy/lib/Drupal/taxonomy/Type/TaxonomyTermReferenceItem.php b/core/modules/taxonomy/lib/Drupal/taxonomy/Type/TaxonomyTermReferenceItem.php
index 395fe88..b558d97 100644
--- a/core/modules/taxonomy/lib/Drupal/taxonomy/Type/TaxonomyTermReferenceItem.php
+++ b/core/modules/taxonomy/lib/Drupal/taxonomy/Type/TaxonomyTermReferenceItem.php
@@ -53,11 +53,10 @@ public function getPropertyDefinitions() {
    * Overrides \Drupal\Core\Entity\Field\FieldItemBase::get().
    */
   public function setValue($values, $notify = TRUE) {
-    // Treat the values as property value of the first property, if no array is
+    // Treat the values as property value of the entity property, if no array is
     // given.
     if (isset($values) && !is_array($values)) {
-      $keys = array_keys($this->getPropertyDefinitions());
-      $values = array($keys[0] => $values);
+      $values = array('entity' => $values);
     }
     // Make sure that the 'entity' property gets set as 'tid'.
     if (isset($values['tid']) && !isset($values['entity'])) {
diff --git a/core/modules/views/views_ui/lib/Drupal/views_ui/ViewUI.php b/core/modules/views/views_ui/lib/Drupal/views_ui/ViewUI.php
index 79a7f99..95cf300 100644
--- a/core/modules/views/views_ui/lib/Drupal/views_ui/ViewUI.php
+++ b/core/modules/views/views_ui/lib/Drupal/views_ui/ViewUI.php
@@ -167,7 +167,7 @@ public function setStatus($status) {
   /**
    * Overrides \Drupal\Core\Config\Entity\ConfigEntityBase::set().
    */
-  public function set($property_name, $value) {
+  public function set($property_name, $value, $notify = TRUE) {
     if (property_exists($this->storage, $property_name)) {
       $this->storage->set($property_name, $value);
     }