diff --git a/modules/oe_theme_helper/templates/oe-theme-helper-inpage-navigation-block.html.twig b/modules/oe_theme_helper/templates/oe-theme-helper-inpage-navigation-block.html.twig
index 2eca1afbd..53250aef3 100644
--- a/modules/oe_theme_helper/templates/oe-theme-helper-inpage-navigation-block.html.twig
+++ b/modules/oe_theme_helper/templates/oe-theme-helper-inpage-navigation-block.html.twig
@@ -9,7 +9,7 @@
   {% include '@ecl-twig/inpage-navigation' with {
     'title': title,
     'icon_path': ecl_icon_path,
-    'extra_classes': 'oe-theme-ecl-inpage-navigation',
+    'extra_classes': 'oe-theme-ecl-inpage-navigation ecl-u-z-dropdown',
     'extra_attributes': [
       {
         'name': 'data-ecl-auto-initialized',
diff --git a/modules/oe_theme_helper/tests/src/FunctionalJavascript/InPageNavigationLibraryTest.php b/modules/oe_theme_helper/tests/src/FunctionalJavascript/InPageNavigationLibraryTest.php
index 25c91d207..fa61cca46 100644
--- a/modules/oe_theme_helper/tests/src/FunctionalJavascript/InPageNavigationLibraryTest.php
+++ b/modules/oe_theme_helper/tests/src/FunctionalJavascript/InPageNavigationLibraryTest.php
@@ -98,7 +98,7 @@ public function testLibrary(): void {
     // The heading starting with a non-alpha character gets a ref- prepended.
     $this->assertEquals('ref-2022-a-new-year', $container->find('xpath', '/h3[@class="heading"][text()="2022, a new year"]')->getAttribute('id'));
 
-    $navigation = $assert_session->elementExists('css', '.oe-theme-ecl-inpage-navigation');
+    $navigation = $assert_session->elementExists('css', '.oe-theme-ecl-inpage-navigation.ecl-u-z-dropdown');
 
     $assert = new InPageNavigationAssert();
     $expected = [
@@ -169,7 +169,7 @@ public function testMultipleContainers(): void {
     $this->assertCount(14, $main_content->findAll('xpath', '//*[@id]'));
 
     $first_container = $main_content->find('css', '.first-container');
-    $navigation = $assert_session->elementExists('css', '.oe-theme-ecl-inpage-navigation', $first_container);
+    $navigation = $assert_session->elementExists('css', '.oe-theme-ecl-inpage-navigation.ecl-u-z-dropdown', $first_container);
     $assert = new InPageNavigationAssert();
     $expected = [
       'title' => 'First nav',
@@ -191,7 +191,7 @@ public function testMultipleContainers(): void {
     $assert->assertPattern($expected, $navigation->getOuterHtml());
 
     $second_container = $main_content->find('css', '.second-container');
-    $navigation = $assert_session->elementExists('css', '.oe-theme-ecl-inpage-navigation', $second_container);
+    $navigation = $assert_session->elementExists('css', '.oe-theme-ecl-inpage-navigation.ecl-u-z-dropdown', $second_container);
     $assert = new InPageNavigationAssert();
     $expected = [
       'title' => 'Second nav',