diff --git a/kernel/model/file.go b/kernel/model/file.go
index b6025e63e..aa08126c1 100644
--- a/kernel/model/file.go
+++ b/kernel/model/file.go
@@ -242,7 +242,7 @@ func ListDocTree(boxID, path string, sortMode int, flashcard bool, maxListCount
 	var deck *riff.Deck
 	var deckBlockIDs []string
 	if flashcard {
-		deck := Decks[builtinDeckID]
+		deck = Decks[builtinDeckID]
 		if nil == deck {
 			return
 		}