diff --git a/core/modules/outside_in/css/outside_in.module.css b/core/modules/outside_in/css/outside_in.module.css
index 9d90bf227d..f9c86c8ca2 100644
--- a/core/modules/outside_in/css/outside_in.module.css
+++ b/core/modules/outside_in/css/outside_in.module.css
@@ -36,3 +36,13 @@
     overflow-y: hidden;
   }
 }
+
+.ui-dialog.outside-edit-message .ui-dialog-titlebar {
+  background: inherit;
+  border: none;
+}
+
+.ui-dialog.outside-edit-message .ui-dialog-titlebar {
+  padding: 0;
+}
+
diff --git a/core/modules/outside_in/js/outside_in.es6.js b/core/modules/outside_in/js/outside_in.es6.js
index 2fb19f8202..4aee4e201b 100644
--- a/core/modules/outside_in/js/outside_in.es6.js
+++ b/core/modules/outside_in/js/outside_in.es6.js
@@ -136,6 +136,7 @@
       },
       autoResize: false,
       draggable: false,
+      dialogClass: 'outside-edit-message',
     }).show();
     announce(editMsg);
     $(msgDiv).on('click.outsidein', e => $(e.target).remove());
diff --git a/core/modules/outside_in/js/outside_in.js b/core/modules/outside_in/js/outside_in.js
index 0f78742d54..5f02e968c4 100644
--- a/core/modules/outside_in/js/outside_in.js
+++ b/core/modules/outside_in/js/outside_in.js
@@ -83,7 +83,8 @@
         of: '.dialog-off-canvas__main-canvas'
       },
       autoResize: false,
-      draggable: false
+      draggable: false,
+      dialogClass: 'outside-edit-message'
     }).show();
     announce(editMsg);
     $(msgDiv).on('click.outsidein', function (e) {
diff --git a/core/modules/outside_in/outside_in.libraries.yml b/core/modules/outside_in/outside_in.libraries.yml
index cce7202d1f..5946d95b75 100644
--- a/core/modules/outside_in/outside_in.libraries.yml
+++ b/core/modules/outside_in/outside_in.libraries.yml
@@ -21,7 +21,6 @@ drupal.outside_in:
     - core/jquery.once
     - core/drupal.ajax
     - core/drupal.announce
-    - core/drupal.debounce
     - toolbar/toolbar
 drupal.off_canvas:
   version: VERSION
diff --git a/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php b/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php
index 107a055283..9a6e166588 100644
--- a/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php
+++ b/core/modules/outside_in/tests/src/FunctionalJavascript/OutsideInBlockFormTest.php
@@ -214,6 +214,7 @@ protected function openBlockForm($block_selector) {
     $this->click($block_selector);
     $this->waitForOffCanvasToOpen();
     $this->assertOffCanvasBlockFormIsValid();
+    $this->closeMessageDialog();
   }
 
   /**
@@ -352,6 +353,7 @@ protected function assertEditModeEnabled() {
     // The main canvas element should have the "js-outside-in-edit-mode" class.
     $web_assert->elementExists('css', '.dialog-off-canvas__main-canvas.js-outside-in-edit-mode');
     $web_assert->elementTextContains('css', '#settings-tray-edit-message', 'You are now in edit mode');
+    $this->closeMessageDialog();
   }
 
   /**
@@ -471,4 +473,16 @@ public function getBlockSelector(Block $block) {
     return '#block-' . $block->id();
   }
 
+  /**
+   * Closes the message dialog that contains "You are in edit mode." message.
+   *
+   *  Also waits for the dialog to be removed from the page.
+   */
+  protected function closeMessageDialog() {
+    if ($message_dialog_close_button = $this->assertSession()->waitForElementVisible('css', '[aria-describedby="settings-tray-edit-message"] .ui-dialog-titlebar-close')) {
+      $message_dialog_close_button->click();
+      $this->waitForNoElement('css', '[aria-describedby="settings-tray-edit-message"]');
+    }
+  }
+
 }