diff --git a/core/modules/contact/contact.module b/core/modules/contact/contact.module
index 431efe4..7df0286 100644
--- a/core/modules/contact/contact.module
+++ b/core/modules/contact/contact.module
@@ -162,6 +162,7 @@ function contact_menu_local_tasks_alter(&$data, $router_item, $root_path) {
     }
     // Expand the dynamic argument into a tab for each type.
     $entities = entity_load_multiple('contact_category');
+    uasort($entities, 'Drupal\Core\Config\Entity\ConfigEntityBase::sort');
     $default = config('contact.settings')->get('default_category');
     foreach ($entities as $entity) {
       if ($entity->id() === $default) {
@@ -349,6 +350,12 @@ function contact_field_extra_fields() {
       'description' => t('Option: Send copy to sender'),
       'weight' => 50,
     );
+
+    $fields['contact_message'][$bundle]['display']['message'] = array(
+      'label' => t('Message'),
+      'description' => t('The main contact message'),
+      'weight' => 0,
+    );
   }
   return $fields;
 }
@@ -396,7 +403,7 @@ function contact_mail($key, &$message, $params) {
     '!form-url' => url(current_path(), array('absolute' => TRUE, 'language' => $language)),
     '!sender-name' => user_format_name($sender),
   );
-  if ($sender->uid) {
+  if (!empty($sender->uid)) {
     $sender_uri = $sender->uri();
     $variables['!sender-url'] = url($sender_uri['path'], array('absolute' => TRUE, 'language' => $language) + $sender_uri['options']);
   }
@@ -411,7 +418,7 @@ function contact_mail($key, &$message, $params) {
     case 'page_copy':
       $message['subject'] .= t('[!category] !subject', $variables, $options);
       $message['body'][] = t("!sender-name (!sender-url) sent a message using the contact form at !form-url.", $variables, $options);
-      $message['body'][] = $contact_message->message;
+      $message['body'][] = entity_view($contact_message, 'mail', $language->langcode);
       break;
 
     case 'page_autoreply':
diff --git a/core/modules/contact/contact.pages.inc b/core/modules/contact/contact.pages.inc
index b38d14e..1e53b76 100644
--- a/core/modules/contact/contact.pages.inc
+++ b/core/modules/contact/contact.pages.inc
@@ -45,7 +45,6 @@ function contact_site_page(Category $category = NULL) {
       }
     }
   }
-  // @todo Add 'uid' or 'sender' property and set property here?
   $message = entity_create('contact_message', array(
     'category' => $category->id(),
   ));
diff --git a/core/modules/contact/lib/Drupal/contact/MessageFormController.php b/core/modules/contact/lib/Drupal/contact/MessageFormController.php
index 5bb37b9..e536675 100644
--- a/core/modules/contact/lib/Drupal/contact/MessageFormController.php
+++ b/core/modules/contact/lib/Drupal/contact/MessageFormController.php
@@ -29,11 +29,7 @@ public function form(array $form, array &$form_state, EntityInterface $message)
         '#theme_wrappers' => array('container__preview'),
         '#attributes' => array('class' => array('preview')),
       );
-      $form['preview']['message'] = entity_view($message, 'preview');
-
-      $form['preview']['mail'] = entity_view($message, 'mail');
-      $form['preview']['mail']['#prefix'] = '<pre>';
-      $form['preview']['mail']['#suffix'] = '</pre>';
+      $form['preview']['message'] = entity_view($message, 'full');
     }
 
     $form['name'] = array(
@@ -58,14 +54,15 @@ public function form(array $form, array &$form_state, EntityInterface $message)
       $form['name']['#value'] = $user->name;
       $form['name']['#required'] = FALSE;
       $form['name']['#markup'] = check_plain(user_format_name($user));
+
       $form['mail']['#type'] = 'item';
       $form['mail']['#value'] = $user->mail;
       $form['mail']['#required'] = FALSE;
       $form['mail']['#markup'] = check_plain($user->mail);
     }
 
-    // If there is a recipient, then this is a user contact form and there is no
-    // category.
+    // The user contact form only has a recipient, not a category.
+    // @todo Convert user contact form into a locked contact category.
     if ($message->recipient instanceof User) {
       $form['recipient'] = array(
         '#type' => 'item',
@@ -77,42 +74,12 @@ public function form(array $form, array &$form_state, EntityInterface $message)
         ),
       );
     }
-    // The site-wide contact form always passes a category and defaults to the
-    // configured default category.
-    elseif (!empty($message->category)) {
+    else {
       $form['category'] = array(
         '#type' => 'value',
         '#value' => $message->category,
       );
     }
-    // There may be other callers, which request this form without a category.
-    // In this case, the Message entity automatically sets 'fieldable' to FALSE.
-    // @todo Consider to remove this fallback.
-    else {
-      // Prepare array for select options.
-      $categories = entity_load_multiple('contact_category');
-      uasort($categories, 'Drupal\Core\Config\Entity\ConfigEntityBase::sort');
-      $options = array();
-      foreach ($categories as $category) {
-        $options[$category->id()] = $category->label();
-      }
-      // If there is more than one category available and no default category has
-      // been selected, prepend a default placeholder value.
-      $config = config('contact.settings');
-      $default_category = $config->get('default_category');
-      if (!$default_category) {
-        $default_category = !empty($categories) ? key($categories) : NULL;
-      }
-      $form['category'] = array(
-        '#type' => 'select',
-        '#title' => t('Category'),
-        '#default_value' => $default_category,
-        '#options' => $options,
-        '#empty_value' => 0,
-        '#required' => TRUE,
-        '#access' => count($categories) > 1,
-      );
-    }
 
     $form['subject'] = array(
       '#type' => 'textfield',
@@ -157,6 +124,9 @@ public function actions(array $form, array &$form_state) {
     return $elements;
   }
 
+  /**
+   * Form submission handler for the 'preview' action.
+   */
   public function preview(array $form, array &$form_state) {
     $message = $this->getEntity($form_state);
     $message->preview = TRUE;
@@ -168,13 +138,14 @@ public function preview(array $form, array &$form_state) {
    */
   public function save(array $form, array &$form_state) {
     global $user;
+
     $language_interface = language(LANGUAGE_TYPE_INTERFACE);
     $message = $this->getEntity($form_state);
 
     $sender = clone user_load($user->uid);
     if (!$user->uid) {
-      // At this point, $message->sender contains drupal_anonymous_user(), so we
-      // need to take over the submitted form values.
+      // At this point, $sender contains drupal_anonymous_user(), so we need to
+      // take over the submitted form values.
       $sender->name = $message->name;
       $sender->mail = $message->mail;
       // Save the anonymous user information to a cookie for reuse.
@@ -188,12 +159,11 @@ public function save(array $form, array &$form_state) {
     $params['contact_message'] = $message;
     $params['sender'] = $sender;
 
-    // @todo Category should be available in $form_state to hook_form_alter() already.
     if ($message->category) {
+      // Send to the category recipient(s), using the site's default language.
       $category = entity_load('contact_category', $message->category);
       $params['contact_category'] = $category;
 
-      // Send to configured recipient(s), using the site's default language.
       $to = implode(', ', $category->recipients);
       $recipient_langcode = language_default()->langcode;
     }
@@ -203,7 +173,7 @@ public function save(array $form, array &$form_state) {
       $recipient_langcode = user_preferred_langcode($message->recipient);
     }
     else {
-      throw new \RuntimeException('Unable to determine message recipient.');
+      throw new \RuntimeException(t('Unable to determine message recipient.'));
     }
 
     // Send e-mail to the recipient(s).
diff --git a/core/modules/contact/lib/Drupal/contact/MessageRenderController.php b/core/modules/contact/lib/Drupal/contact/MessageRenderController.php
index a2163b9..3044a85 100644
--- a/core/modules/contact/lib/Drupal/contact/MessageRenderController.php
+++ b/core/modules/contact/lib/Drupal/contact/MessageRenderController.php
@@ -15,12 +15,37 @@
  */
 class MessageRenderController extends EntityRenderController {
 
+  /**
+   * Overrides Drupal\Core\Entity\EntityRenderController::buildContent().
+   */
+  public function buildContent(array $entities = array(), $view_mode = 'full', $langcode = NULL) {
+    parent::buildContent($entities, $view_mode, $langcode);
+
+    foreach ($entities as $entity) {
+      // Add the message extra field, if enabled.
+      $bundle = $entity->bundle();
+      $entity_view_mode = $entity->content['#view_mode'];
+      $fields = field_extra_fields_get_display($this->entityType, $bundle, $entity_view_mode);
+      if (!empty($entity->message) && !empty($fields['message']['visible'])) {
+        $entity->content['message'] = array(
+          '#type' => 'item',
+          '#title' => t('Message'),
+          '#markup' => check_plain($entity->message),
+          '#weight' => $fields['message']['weight'],
+        );
+      }
+    }
+  }
+
+  /**
+   * Overrides Drupal\Core\Entity\EntityRenderController::view().
+   */
   public function view(EntityInterface $entity, $view_mode = 'full', $langcode = NULL) {
     $build = parent::view($entity, $view_mode, $langcode);
 
     if ($view_mode == 'mail') {
-      // Convert field labels into headings, as long as drupal_html_to_text()
-      // fails to convert DIVs correctly.
+      // Convert field labels into headings.
+      // @todo Improve drupal_html_to_text() to convert DIVs correctly.
       foreach (element_children($build) as $key) {
         if (isset($build[$key]['#label_display']) && $build[$key]['#label_display'] == 'above') {
           $build[$key] += array('#prefix' => '');