diff --git a/src/Element/ComponentForm.php b/src/Element/ComponentForm.php
index d26a0b5d96c5b35d3c7c4cb26ff976fcb13fd6b4..89de156be82e3bc4792a0bb9af725fc172c5d587 100644
--- a/src/Element/ComponentForm.php
+++ b/src/Element/ComponentForm.php
@@ -113,12 +113,12 @@ class ComponentForm extends ComponentFormBase {
       $element['#source_contexts']['component_id'] = new Context($contextComponentDefinition, $component_id);
     }
     if ($initial_component_id === NULL) {
-      $element["component_id"] = self::expandAjax(self::buildComponentSelectorForm(
+      $component_selector_form = array_merge(self::buildComponentSelectorForm(
         $wrapper_id,
         $component_id
-      ));
+      ), ["#ajax_url" => $element["#ajax_url"]]);
+      $element["component_id"] = self::expandAjax($component_selector_form);
     }
-
     self::buildComponentForm(
       $element,
       $wrapper_id,
@@ -241,7 +241,7 @@ class ComponentForm extends ComponentFormBase {
       '#component_id' => $component_id,
       '#source_contexts' => $element['#source_contexts'],
       '#tag_filter' => $element['#tag_filter'],
-      '#ajax_url' => $element['#ajax_url'] ?? "",
+      '#ajax_url' => $element['#ajax_url'],
       '#access' => $element['#render_props'] ?? TRUE,
       '#default_value' => [
         'props' => $element['#default_value']['props'],