diff --git a/lib/hooks/search-threads.js b/lib/hooks/search-threads.js
--- a/lib/hooks/search-threads.js
+++ b/lib/hooks/search-threads.js
@@ -48,9 +48,11 @@
     );
   }, [childThreadInfos, searchState]);
 
-  const searchIndex = useThreadSearchIndex(
-    childThreadInfos.map(childThreadInfo => childThreadInfo.threadInfo),
+  const justThreadInfos = React.useMemo(
+    () => childThreadInfos.map(childThreadInfo => childThreadInfo.threadInfo),
+    [childThreadInfos],
   );
+  const searchIndex = useThreadSearchIndex(justThreadInfos);
 
   const onChangeSearchInputText = React.useCallback(
     (text: string) => {