diff --git a/src/Plugin/facets/widget/CheckboxWidget.php b/src/Plugin/facets/widget/CheckboxWidget.php
index 877e478..eb7e23e 100644
--- a/src/Plugin/facets/widget/CheckboxWidget.php
+++ b/src/Plugin/facets/widget/CheckboxWidget.php
@@ -113,7 +113,7 @@ class CheckboxWidget implements WidgetInterface, FormInterface {
       $options[$result->getRawValue()] = $text;
 
       if ($result->isActive()) {
-        $form[$facet->getFieldAlias()]['#default_value'] = $result->getRawValue();
+        $form[$facet->getFieldAlias()]['#default_value'][] = $result->getRawValue();
       }
     }
 
@@ -159,11 +159,12 @@ class CheckboxWidget implements WidgetInterface, FormInterface {
 
     // We have an active item, so redirecting to that page.
     if ($result_link instanceof Url) {
-      return new RedirectResponse($result_link->toString());
+      $form_state->setResponse(new RedirectResponse($result_link->toString()));
+      return;
     }
 
     // Form was submitted, but nothing was selected, so we should submit to the
     // facet.
-    return new RedirectResponse('/' . $facet->getFacetSource()->getPath());
+    $form_state->setResponse(new RedirectResponse('/' . $facet->getFacetSource()->getPath()));
   }
 }