Wim Leers · Wim Leers · Wim Leers
--- a/src/Controller/ApiLayoutController.php
+++ b/src/Controller/ApiLayoutController.php

  private function addGlobalRegions(PageTemplate $template, array &$model, array &$layout): void {
+    $active_component_trees = iterator_to_array($template->getComponentTrees());
+    // Only expose regions marked as editable in the `layout` for the client.
+    // @see experience_builder_form_system_theme_settings_alter()
+    $editable_regions = array_keys(array_filter($template->get('editable')));
+
    $draft_template = $this->autoSaveManager->getAutoSaveData($template);
    if ($draft_template === NULL) {
-      foreach ($template->getComponentTrees() as $region => $tree) {
+      foreach ($editable_regions as $region) {
        if ($region === 'content') {
          continue;
        }
-        $layout[] = $this->buildRegion($region, $tree, $model);
+        $layout[] = $this->buildRegion($region, $active_component_trees[$region] ?? NULL, $model);
--- a/src/Controller/ApiLayoutController.php
+++ b/src/Controller/ApiLayoutController.php
+    // editable regions.
+    $draft_layout_region_nodes = array_filter($draft_template['layout'], fn (array $layout_node): bool => $layout_node['nodeType'] === 'region');
+    $autosaved_regions = array_column($draft_layout_region_nodes, 'id');
+    $missing_regions_in_auto_save = array_diff($editable_regions, $autosaved_regions);
+    foreach ($missing_regions_in_auto_save as $region) {
+      if ($region === 'content') {
+        continue;
+      }
+      $layout[] = $this->buildRegion($region, $active_component_trees[$region] ?? NULL, $model);
+    }
+    $extraneous_regions_in_auto_save = array_diff($autosaved_regions, $editable_regions);
+    foreach ($extraneous_regions_in_auto_save as $region) {
+      foreach ($draft_template['layout'] as $index => $region_node) {
+        if ($region_node['id'] === $region) {
+          unset($draft_template['layout'][$index]);
+          // @todo In principle, $model should be updated too, to omit props for components in the omitted regions. There's no consequences yet for not doing that though.
--- a/src/EventSubscriber/RenderEventsSubscriber.php
+++ b/src/EventSubscriber/RenderEventsSubscriber.php
    if ($preview && $autoSaveData = $this->autoSaveManager->getAutoSaveData($page_template)) {
      // Generate a new template based on the auto-saved data.
      try {
-        $page_template = $page_template->forAutoSaveData($autoSaveData)->enable();
+        $autosaved_page_template = $page_template->forAutoSaveData($autoSaveData)->enable();
+        // There are fewer region component trees auto-saved than there are
+        // regions when some of them are marked as not editable. For the regions
+        // that cannot be edited: load them from the active page template.
+        // @see experience_builder_form_system_theme_settings_alter()
+        if (count($autosaved_page_template->get('component_trees')) < count($page_template->get('editable'))) {
+          $autosaved_page_template->set('component_trees',
+            $autosaved_page_template->get('component_trees')
+            +
+            $page_template->get('component_trees')
--- a/src/Plugin/DisplayVariant/PageTemplateDisplayVariant.php
+++ b/src/Plugin/DisplayVariant/PageTemplateDisplayVariant.php
        if ($region === 'content') {
          continue;
        }
+        // Do not wrap regions marked as not editable; this causes visible whitespace.
+        // @see experience_builder_form_system_theme_settings_alter()
+        if ($page_template->get('editable')[$region] === FALSE) {
+          continue;
+        }