Alert Not Firing

Hello,
I currently have an alert setup as follows:
Object: SQLServer:Transactions
Counter: Longest Transaction Running Time
Alert if counter: rises above
Value: 3

I then run the following code via query analyzer:CREATE TABLE T1(Col1 int, Col2 char(3));
GO
BEGIN TRAN
INSERT INTO T1 VALUES (101, 'abc');
GO
WAITFOR DELAY '00:00:06'
DBCC OPENTRAN
ROLLBACK TRAN
GO
DROP TABLE T1;
GO
Yet no alert fires. I would have expected it to fire since this transaction takes longer than 3 seconds.