diff --git a/classes/output/navigation/primary.php b/classes/output/navigation/primary.php
index ded227a4396..b49e948bc75 100644
--- a/classes/output/navigation/primary.php
+++ b/classes/output/navigation/primary.php
@@ -108,7 +108,8 @@ public function export_for_template(?renderer_base $output = null): array {
         $locationbottom = smartmenu::get_menus_forlocation(smartmenu::LOCATION_BOTTOM, $smartmenus);
 
         // Merge the smart menu nodes which contain the main menu location with the primary and custom menu nodes.
-        $menudata = array_merge($this->get_primary_nav(), $this->get_custom_menu($output), $mainmenu);
+        $mainsmartmenumergedcustom = array_merge($this->get_custom_menu($output), $mainmenu);
+        $menudata = (object) $this->merge_primary_and_custom($this->get_primary_nav(), $mainsmartmenumergedcustom);
         $moremenu = new \core\navigation\output\more_menu((object) $menudata, 'navbar-nav', false);
 
         // Menubar.
@@ -120,9 +121,10 @@ public function export_for_template(?renderer_base $output = null): array {
 
         // Bottom bar.
         // Include the menu navigation menus to the mobile menu when the bottom bar doesn't have any menus.
+        $mergecustombottommenus = array_merge($this->get_custom_menu($output), $locationbottom);
         $mobileprimarynav = (!empty($locationbottom))
-            ? array_merge($this->get_primary_nav(), $this->get_custom_menu($output), $locationbottom)
-            : $mobileprimarynav = $menudata;
+            ? $this->merge_primary_and_custom($this->get_primary_nav(), $mergecustombottommenus, true)
+            : $this->merge_primary_and_custom($this->get_primary_nav(), $mainsmartmenumergedcustom, true);
 
         if (!empty($mobileprimarynav)) {
             $bottombar = new \core\navigation\output\more_menu((object) $mobileprimarynav, 'navbar-nav-bottom-bar', false);
@@ -307,4 +309,86 @@ public function build_usermenus(&$usermenu, $menus) {
             array_push($usermenu['items'], $logout);
         }
     }
+
+    /**
+     * Recursive checks if any of the children is active. If that's the case this node (the parent) is active as
+     * well. If the node has no children, check if the node itself is active. Use pass by reference for the node
+     * object because we actively change/set the "isactive" flag inside the method and this needs to be kept at the
+     * callers side.
+     * Set $expandedmenu to true, if the mobile menu is done, in this case the active flag gets the node that is
+     * actually active, while the parent hierarchy of the active node gets the flag isopen.
+     *
+     * Modifications compared to the original function:
+     * * Updated the children node type to object
+     *
+     * @param object $node
+     * @param bool $expandedmenu
+     * @return bool
+     */
+    protected function flag_active_nodes(object $node, bool $expandedmenu = false): bool {
+        global $FULLME;
+        $active = false;
+        foreach (array_keys($node->children ?? []) as $c) {
+
+            // Update the type of child nodes (smart menu).
+            // To prevent issues with already configured menus,
+            // The type of children is not updated during the smart menu build process.
+            $child = (object) $node->children[$c];
+
+            if ($this->flag_active_nodes($child, $expandedmenu)) {
+                $active = true;
+            }
+        }
+        // One of the children is active, so this node (the parent) is active as well.
+        if ($active) {
+            if ($expandedmenu) {
+                $node->isopen = true;
+            } else {
+                $node->isactive = true;
+            }
+            return true;
+        }
+
+        // By default, the menu item node to check is not active.
+        $node->isactive = false;
+
+        // Check if the node url matches the called url. The node url may omit the trailing index.php, therefore check
+        // this as well.
+        if (empty($node->url)) {
+            // Current menu node has no url set, so it can't be active.
+            return false;
+        }
+        $nodeurl = parse_url($node->url);
+        $current = parse_url($FULLME ?? '');
+
+        $pathmatches = false;
+
+        // Exact match of the path of node and current url.
+        $nodepath = $nodeurl['path'] ?? '/';
+        $currentpath = $current['path'] ?? '/';
+        if ($nodepath === $currentpath) {
+            $pathmatches = true;
+        }
+        // The current url may be trailed by a index.php, otherwise it's the same as the node path.
+        if (!$pathmatches && $nodepath . 'index.php' === $currentpath) {
+            $pathmatches = true;
+        }
+        // No path did match, so the node can't be active.
+        if (!$pathmatches) {
+            return false;
+        }
+        // We are here because the path matches, so now look at the query string.
+        $nodequery = $nodeurl['query'] ?? '';
+        $currentquery = $current['query'] ?? '';
+        // If the node has no query string defined, then the patch match is sufficient.
+        if (empty($nodeurl['query'])) {
+            $node->isactive = true;
+            return true;
+        }
+        // If the node contains a query string then also the current url must match this query.
+        if ($nodequery === $currentquery) {
+            $node->isactive = true;
+        }
+        return $node->isactive;
+    }
 }
diff --git a/version.php b/version.php
index b395416e939..2872aa17ff3 100644
--- a/version.php
+++ b/version.php
@@ -25,7 +25,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 $plugin->component = 'theme_boost_union';
-$plugin->version = 2023102035;
+$plugin->version = 2023102036;
 $plugin->release = 'v4.3-r12';
 $plugin->requires = 2023100900;
 $plugin->supported = [403, 403];