diff -u b/core/includes/config.inc b/core/includes/config.inc
--- b/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -18,16 +18,30 @@
 /**
  * Installs the default configuration of a given extension.
  *
+ * When an extension is installed, it searches all the default configuration
+ * directories for all other extensions to locate any configuration with its
+ * name prefix. For example, the Node module provides the frontpage view as a
+ * default configuration file:
+ * core/modules/node/config/views.view.frontpage.yml
+ * When the Views module is installed after the Node module is already enabled,
+ * the frontpage view will be installed.
+ *
+ * Additionally, the default configuration directory for the extension being
+ * installed is searched to discover if it contains default configuration
+ * that is owned by other enabled extensions. So, the frontpage view will also
+ * be installed when the Node module is installed after Views.
+ *
  * @param string $type
  *   The extension type; e.g., 'module' or 'theme'.
  * @param string $name
  *   The name of the module or theme to install default configuration for.
+ *
+ * @see \Drupal\Core\Config\ExtensionInstallStorage
+ * @see \Drupal\Core\Config\ExtensionInstallStorageComparer
+ * @see \Drupal\Core\Config\ConfigInstaller
  */
 function config_install_default_config($type, $name) {
-  // Get all default configuration owned by this extension. This will return any
-  // configuration that starts with the extension name that exists in any
-  // enabled extension's config directory. This includes the extension that is
-  // being installed.
+  // Get all default configuration owned by this extension.
   $source_storage = new ExtensionInstallStorage();
   $config_to_install = $source_storage->listAll($name . '.');
 
only in patch2:
unchanged:
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1476,15 +1476,16 @@ function theme_enable($theme_list) {
     }
 
     // The value is not used; the weight is ignored for themes currently.
-    $theme_config->set("enabled.$key", 0);
-    $disabled_themes->clear($key);
+    $theme_config->set("enabled.$key", 0)->save();;
+    $disabled_themes->clear($key)->save();
+
+    // Refresh the theme list as config_install_default_config() needs an
+    // updated list to work.
+    list_themes(TRUE);
     // Install default configuration of the theme.
     config_install_default_config('theme', $key);
   }
-  $theme_config->save();
-  $disabled_themes->save();
 
-  list_themes(TRUE);
   Drupal::service('router.builder')->rebuild();
   menu_router_rebuild();
   drupal_theme_rebuild();