UIAvtionSheetのキャンセルボタンが効かない？

ツールバーがあるとActionSheetのキャンセルボタンの下半分がきかない。

変更前

UIActionSheet *actionSheet = [[UIActionSheet alloc] init];
actionSheet.title = @"タイトル";
[actionSheet addButtonWithTitle:@"決定"];
[actionSheet addButtonWithTitle:@"キャンセル"];
actionSheet.cancelButtonIndex = 1;
actionSheet.destructiveButtonIndex = 0;
actionSheet.delegate = self;
[actionSheet showInView:self.view];

変更後

UIActionSheet *actionSheet = [[UIActionSheet alloc] init];
actionSheet.title = @"タイトル";
[actionSheet addButtonWithTitle:@"決定"];
[actionSheet addButtonWithTitle:@"キャンセル"];
actionSheet.cancelButtonIndex = 1;
actionSheet.destructiveButtonIndex = 0;
actionSheet.delegate = self;
[sheet showInView:self.view.window];