IN bug

Hi all,
Seems there is a bug on IN (subselect)

I'm looking for duplicate rows and I found 2:

select ename from emp group by ename having 1 < count(ename);
ename
-----
ALLEN
BLAKE
(2 rows)

Using IN to display all columns of duplicate rows I have the
following:

select * from emp where ename in (
select ename from emp group by ename having 1 < count(ename)
);
ename |empno|job | hiredate|sal |comm|deptno|level| mgr
------+-----+----------+----------+---------+----+------+-----+----
ALLEN | 7499|SALESMAN |1981-02-20|$1,600.00| 300| 20| 4|7782
BLAKE | 7698|MANAGER |1981-05-01|$2,850.00| | 30| 3|7782
JONES | 7900|CLERK |1981-12-03|$950.00 | | 30| 2|7782
MILLER| 7654|SALESMAN |1981-09-28|$1,250.00| 400| 30| 3|7839
CLARK | 7844|SALESMAN |1981-09-08|$1,500.00| | 10| 2|7839
KING | 7521|SALESMAN |1981-02-22|$1,250.00| 500| 10| 1|7782
ALLEN | 7499|SALESMAN |1981-02-20|$1,600.00| 300| 20| 4|7782
BLAKE | 7698|MANAGER |1981-05-01|$2,850.00| | 30| 3|7782
(8 rows)

but I expect the following instead:

ename |empno|job | hiredate|sal |comm|deptno|level| mgr
------+-----+----------+----------+---------+----+------+-----+----
ALLEN | 7499|SALESMAN |1981-02-20|$1,600.00| 300| 20| 4|7782
BLAKE | 7698|MANAGER |1981-05-01|$2,850.00| | 30| 3|7782
ALLEN | 7499|SALESMAN |1981-02-20|$1,600.00| 300| 20| 4|7782
BLAKE | 7698|MANAGER |1981-05-01|$2,850.00| | 30| 3|7782
(4 rows)

-Jose'-