diff --git a/core/lib/Drupal/Core/Render/MainContent/AjaxRenderer.php b/core/lib/Drupal/Core/Render/MainContent/AjaxRenderer.php
index 31192f3..dcef39d 100644
--- a/core/lib/Drupal/Core/Render/MainContent/AjaxRenderer.php
+++ b/core/lib/Drupal/Core/Render/MainContent/AjaxRenderer.php
@@ -72,8 +72,8 @@ public function renderResponse(array $main_content, Request $request, RouteMatch
     // behavior can be changed with #ajax['method'].
     $response->addCommand(new InsertCommand(NULL, $html));
     $status_messages = array('#type' => 'status_messages');
-    $output = $this->drupalRenderRoot($status_messages);
-    if (!empty($output)) {
+    $output_trimmed = trim($this->drupalRenderRoot($status_messages));
+    if (!empty($output_trimmed)) {
       $response->addCommand(new PrependCommand(NULL, $output));
     }
     return $response;