Replace is_panelized by has_page_layout variable.

assets/scss/layouts/_content-layouts.scss

@@ -48,15 +48,15 @@
   }
 }
 
-// Add space above footer region for all pages except the panelized ones.
-.au-body:not(.is-panelized) {
+// Add space above footer region for all pages except the ones using GovCMS8 Layouts page layout.
+.au-body:not(.has-page-layout) {
   .au-footer {
     @include AU-space(margin-top, 2unit);
   }
 }
 
-// Add space below content region for all panelized pages except the edgy.
-.au-body.is-panelized .page-layout:not(.page-layout--edgy) {
+// Add space below content region for all pages using GovCMS8 Layouts page layout except the edgy.
+.au-body.has-page-layout .page-layout:not(.page-layout--edgy) {
   @include AU-space(margin-bottom, 2unit);
 }
 

assets/scss/layouts/_page-layout.scss

@@ -1,4 +1,4 @@
-// Non panelized pages needs space between page title and content.
+// Pages not using GovCMS8 Layouts page layout needs space between page title and content.
 .au-grid > .content-top {
   @include AU-space(margin-bottom, $AU-grid-12-gutter-width);
 }

govcms8_uikit_starter.theme

@@ -123,20 +123,10 @@ function govcms8_uikit_starter_preprocess_page(&$variables) {
   ];
   govcms8_uikit_starter_theme_settings_mappings($variables, $theme_settings_mappings);
 
-  // Check if current page is defined by Page manager.
-  $route = RouteMatch::createFromRequest(\Drupal::request());
-  $parameters = $route->getParameters();
-
-  // Check if node is panelized.
-  if ($parameters->has('node')) {
-    /** @var \Drupal\node\Entity\Node $node */
-    $node = $parameters->get('node');
-    // If Panelizer is enabled for this node type.
-    if (is_object($node) && $node->hasField('panelizer')) {
-      // Set is_panelized variable.
-      $variables['is_panelized'] = TRUE;
-    }
-  }
+  // Set flag saying if current page is using any page layout.
+  $variables['has_page_layout'] = drupal_static('govcms8_layouts_page', FALSE);
+  // Set also old flag name backward compatibility.
+  $variables['is_panelized'] = $variables['has_page_layout'];
 }
 
 /**
@@ -302,11 +292,20 @@ function govcms8_uikit_starter_theme_find_active_link(array &$links, $path) {
 function govcms8_uikit_starter_preprocess_layout(&$variables) {
   /** @var \Drupal\Core\Layout\LayoutDefinition $layout */
   $layout = $variables['layout'];
+
+  // Only if current layout is inside "GovCMS8 Layouts" module.
+  if ($layout->getProvider() === 'govcms8_layouts') {
+    // Set "has_page_layout" flag into static variable storage.
+    if (substr($layout->id(), 0, 5) === 'page_') {
+      drupal_static('govcms8_layouts_page', TRUE);
+    }
+  }
+
+  // Add Design System Card classes to the stack layout.
   if (in_array($layout->id(), [
     'stack_detail',
     'stack_simple',
   ])) {
-    // Add Design System Card classes to the stack layout.
     $variables['attributes']['class'][] = 'au-card';
     $variables['attributes']['class'][] = 'au-body';
     $variables['attributes']['class'][] = 'au-card--shadow';
@@ -316,7 +315,7 @@ function govcms8_uikit_starter_preprocess_layout(&$variables) {
 
     // Only if Item url field is not empty or Display suite title link is set.
     if (($entity->hasField('field_item_url') && !$entity->get('field_item_url')->isEmpty())
-        || !empty($variables['content']['title']['node_title'][0][0]['#context']['is_link'])
+      || !empty($variables['content']['title']['node_title'][0][0]['#context']['is_link'])
     ) {
       // Add au-card--clickable class to Card.
       $variables['attributes']['class'][] = 'au-card--clickable';

templates/layout/page.html.twig

@@ -48,7 +48,7 @@
   'au-grid',
   'layout-container',
   theme__highlighted_layouts ? theme__highlighted_layouts,
-  is_panelized ? 'is-panelized',
+  has_page_layout ? 'has-page-layout',
 ]
 %}
 
@@ -74,8 +74,8 @@
     </div>
   {% endif %}
 
-  {# Page title and breadcrumbs for all pages except the panelized ones. #}
-  {% if not is_panelized %}
+  {# Page title and breadcrumbs for all pages except the ones using GovCMS8 Layouts page layout. #}
+  {% if not has_page_layout %}
     {% if page.content_top|render|striptags|trim is not empty %}
       <div class="content-top">
         <div class="container">
@@ -89,15 +89,14 @@
   <main>
     <a id="main-content" tabindex="-1"></a>{# link is in html.html.twig #}
 
-    {# Template for panelized node pages. #}
-    {% if is_panelized %}
+    {# Template for node pages using GovCMS8 Layouts page layout. #}
+    {% if has_page_layout %}
       <div class="main-content">
         {{ page.content }}
       </div>{# /.layout-content #}
 
     {% else %}
-      {# Default layout for all pages except the panelized ones, with optional sidebar. #}
-
+      {# Default layout for all pages except the ones using GovCMS8 Layouts page layout, with optional sidebar. #}
       <div class="container">
 
         {% if page.sidebar|render|striptags|trim %}