diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -82,6 +82,7 @@
   threadTypeIsSidebar,
   threadTypeIsPrivate,
   threadTypeIsPersonal,
+  type ThinThreadType,
 } from '../types/thread-types-enum.js';
 import type {
   LegacyRawThreadInfo,
@@ -1335,7 +1336,7 @@
 type ThreadTypeParentRequirement = 'optional' | 'required' | 'disabled';
 
 function getThreadTypeParentRequirement(
-  threadType: ThreadType,
+  threadType: ThinThreadType,
 ): ThreadTypeParentRequirement {
   if (
     threadType === threadTypes.COMMUNITY_OPEN_SUBTHREAD ||