diff --git a/kernel/model/block.go b/kernel/model/block.go
index 863fd9bab..aec5668b9 100644
--- a/kernel/model/block.go
+++ b/kernel/model/block.go
@@ -276,6 +276,7 @@ func GetUnfoldedParentID(id string) (parentID string) {
 	for parent := treenode.HeadingParent(node); nil != parent && ast.NodeDocument != parent.Type; parent = treenode.HeadingParent(parent) {
 		if "1" == parent.IALAttr("fold") {
 			firstFoldedParent = parent
+			parentID = firstFoldedParent.ID
 		}
 		if "1" != parent.IALAttr("fold") {
 			if nil != firstFoldedParent {