diff -u b/core/modules/inline_form_errors/src/FormErrorHandler.php b/core/modules/inline_form_errors/src/FormErrorHandler.php
--- b/core/modules/inline_form_errors/src/FormErrorHandler.php
+++ b/core/modules/inline_form_errors/src/FormErrorHandler.php
@@ -55,7 +55,7 @@
   protected function displayErrorMessages(array $form, FormStateInterface $form_state) {
     // Use the original error display for Quick Edit forms, because in this case
     // the errors are already near the form element.
-    if ($form['#form_id'] == 'quickedit_field_form') {
+    if ($form['#form_id'] === 'quickedit_field_form') {
       parent::displayErrorMessages($form, $form_state);
       return;
     }
reverted:
--- b/core/modules/inline_form_errors/tests/src/FunctionalJavascript/FormErrorHandlerQuickEditTest.php
+++ /dev/null
@@ -1,92 +0,0 @@
-<?php
-
-namespace Drupal\Tests\inline_form_errors\FunctionalJavascript;
-
-use Drupal\FunctionalJavascriptTests\JavascriptTestBase;
-use Drupal\node\Entity\NodeType;
-
-/**
- * Tests Inline Form Errors compatibility with Quick Edit.
- *
- * @group inline_form_errors
- */
-class FormErrorHandlerQuickEditTest extends JavascriptTestBase {
-
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = [
-    'quickedit',
-    'node',
-    'inline_form_errors',
-  ];
-
-  /**
-   * An editor user with permissions to access the in-place editor.
-   *
-   * @var \Drupal\user\UserInterface
-   */
-  protected $editorUser;
-
-  /**
-   * {@inheritdoc}
-   */
-  protected function setUp() {
-    parent::setUp();
-
-    // Create a page node type for testing.
-    NodeType::create(['type' => 'page', 'name' => 'page'])->save();
-
-    // Create a user with the permission to use in-place editing.
-    $permissions = [
-      'access content',
-      'create page content',
-      'edit any page content',
-      'access contextual links',
-      'access in-place editing',
-    ];
-    $this->editorUser = $this->drupalCreateUser($permissions);
-    $this->drupalLogin($this->editorUser);
-  }
-
-  /**
-   * Tests that the inline form errors are not visible for Quick Edit forms.
-   */
-  public function testDisabledInlineFormErrors() {
-    $session = $this->getSession();
-    $web_assert = $this->assertSession();
-
-    // Create a page node.
-    $node = $this->drupalCreateNode();
-
-    // Visit the node page.
-    $this->drupalGet('node/' . $node->id());
-
-    // Wait until the quick edit link is available.
-    $web_assert->waitForElement('css', '.quickedit > a');
-
-    // Activate the quick editing mode.
-    $session->executeScript("jQuery('article.node').find('.quickedit > a').click()");
-
-    $web_assert->waitForElement('css', '.quickedit-toolbar');
-
-    // Clear the title field. Trigger a 'keyup' to be able to save the changes.
-    $session->executeScript("jQuery('.field--name-title').text('').trigger('keyup')");
-
-    // Try to save the changes.
-    $save_button = $web_assert->waitForElement('css', '.action-save.quickedit-button');
-    $save_button->click();
-
-    // Wait until the form submission is complete.
-    $web_assert->assertWaitOnAjaxRequest();
-
-    // Assert that no error summary from Inline Form Errors is shown.
-    $web_assert->elementTextNotContains('css', '.quickedit-validation-errors', '1 error has been found');
-
-    // Assert that the required title error is shown.
-    $web_assert->elementTextContains('css', '.quickedit-validation-errors', 'Title field is required.');
-  }
-
-}