diff --git a/core_search_facets/src/Plugin/facets/query_type/CoreNodeSearchDate.php b/core_search_facets/src/Plugin/facets/query_type/CoreNodeSearchDate.php
index 7a83fb4..9312f34 100644
--- a/core_search_facets/src/Plugin/facets/query_type/CoreNodeSearchDate.php
+++ b/core_search_facets/src/Plugin/facets/query_type/CoreNodeSearchDate.php
@@ -114,7 +114,8 @@ class CoreNodeSearchDate extends QueryTypePluginBase {
           $result->setActiveState(TRUE);
           // Sets the children for the current parent..
           if ($parent) {
-            $parent->setChildren($result);
+            $children = array_merge($parent->getChildren(), [$result]);
+            $parent->setChildren($children);
           }
           else {
             $parent = $parent_facet_results[] = $result;
@@ -180,7 +181,8 @@ class CoreNodeSearchDate extends QueryTypePluginBase {
       $parent = end($parent_facet_results);
       if ($parent instanceof ResultInterface) {
         foreach ($facet_results as $result) {
-          $parent->setChildren($result);
+          $children = array_merge($parent->getChildren(), [$result]);
+          $parent->setChildren($children);
           $this->facet->setResults($parent_facet_results);
         }
       }
diff --git a/facets.libraries.yml b/facets.libraries.yml
index 643be6f..8e08f96 100644
--- a/facets.libraries.yml
+++ b/facets.libraries.yml
@@ -30,6 +30,12 @@ drupal.facets.checkbox-widget:
     - core/drupal
     - core/jquery.once
 
+drupal.facets.hierarchical:
+  version: VERSION
+  css:
+    theme:
+      css/hierarchical.css: {}
+
 drupal.facets.dropdown-widget:
   version: VERSION
   js:
diff --git a/js/checkbox-widget.js b/js/checkbox-widget.js
index 7506685..7ca1934 100644
--- a/js/checkbox-widget.js
+++ b/js/checkbox-widget.js
@@ -21,6 +21,8 @@
     // Find all checkbox facet links and give them a checkbox.
     var $links = $('.js-facets-checkbox-links .facet-item a');
     $links.once('facets-checkbox-transform').each(Drupal.facets.makeCheckbox);
+    // Set indeterminate value on parents having an active trail
+    $('.facet-item--expanded.facet-item--active-trail > input').prop("indeterminate", true);
   };
 
   /**
diff --git a/src/Plugin/facets/url_processor/QueryString.php b/src/Plugin/facets/url_processor/QueryString.php
index 1cbfcfd..0e7c491 100644
--- a/src/Plugin/facets/url_processor/QueryString.php
+++ b/src/Plugin/facets/url_processor/QueryString.php
@@ -93,6 +93,13 @@ class QueryString extends UrlProcessorPluginBase {
             unset($filter_params[$key]);
           }
         }
+        if($facet->getUseHierarchy()){
+          // Enable parent id again if exists.
+          $parent_ids = $facet->getHierarchyInstance()->getParentIds($result->getRawValue());
+          if($parent_ids[0]){
+            $filter_params[] = $this->urlAlias . self::SEPARATOR . $parent_ids[0];
+          }
+        }
       }
       // If the value is not active, add the filter string.
       else {
diff --git a/src/Plugin/facets/widget/LinksWidget.php b/src/Plugin/facets/widget/LinksWidget.php
index fe8cba0..7898812 100644
--- a/src/Plugin/facets/widget/LinksWidget.php
+++ b/src/Plugin/facets/widget/LinksWidget.php
@@ -34,6 +34,9 @@ class LinksWidget extends WidgetPluginBase {
       $build['#attached']['library'][] = 'facets/soft-limit';
       $build['#attached']['drupalSettings']['facets']['softLimit'][$facet->id()] = $soft_limit;
     }
+    if($facet->getUseHierarchy()){
+      $build['#attached']['library'][] = 'facets/drupal.facets.hierarchical';
+    }
     return $build;
   }
 
diff --git a/tests/src/Unit/Plugin/widget/LinksWidgetTest.php b/tests/src/Unit/Plugin/widget/LinksWidgetTest.php
index 027b83a..1ea7d00 100644
--- a/tests/src/Unit/Plugin/widget/LinksWidgetTest.php
+++ b/tests/src/Unit/Plugin/widget/LinksWidgetTest.php
@@ -179,7 +179,7 @@ class LinksWidgetTest extends UnitTestCase {
 
     $child = new Result('snake', 'Snake', 5);
     $original_results[1]->setActiveState(TRUE);
-    $original_results[1]->setChildren($child);
+    $original_results[1]->setChildren([$child]);
 
     $facet = new Facet([], 'facets_facet');
     $facet->setResults($original_results);
@@ -201,8 +201,8 @@ class LinksWidgetTest extends UnitTestCase {
       $this->assertEquals($value, $output['#items'][$index]['#title']);
       $this->assertEquals('link', $output['#items'][$index]['#type']);
       if ($index === 1) {
-        $this->assertEquals('active-trail', $output['#items'][$index]['#attributes']['class']);
-        $this->assertEquals(['facet-item', 'expanded'], $output['#items'][$index]['#wrapper_attributes']['class']);
+        $this->assertEquals('is-active', $output['#items'][$index]['#attributes']['class']);
+        $this->assertEquals(['facet-item', 'facet-item--expanded'], $output['#items'][$index]['#wrapper_attributes']['class']);
       }
       else {
         $this->assertEquals(['facet-item'], $output['#items'][$index]['#wrapper_attributes']['class']);