BUG #4021: UUID NULL and not equal query failed

The following bug has been logged online:

Bug reference: 4021
Logged by: Yann ROBIN
Email address: yann(dot)robin(at)withart(dot)fr
PostgreSQL version: 8.3.0 build 140
Operating system: Windows XP SP2
Description: UUID NULL and not equal query failed
Details:

Hi,

I've tried to do a not like query on a UUID field and the row that i'd like
to get has a NULL value for the UUID field, it gives me no result. The
request :

SELECT *
FROM t_account
WHERE Update_Timestamp > '2008-03-09 12:35:10.309000' AND Update_Timestamp
<= '2008-03-09 12:35:37.861000' AND Update_Id !=
'48012851-3aa4-9940-9ab4-b8333da6b45b'

0 result.

The same request without the Update_Id condition :

SELECT *
FROM t_account
WHERE Update_Timestamp > '2008-03-09 12:35:10.309000' AND Update_Timestamp
<= '2008-03-09 12:35:37.861000'

1 result. The Update_Id field is null.

The same request but with a OR IS NULL condition :

SELECT *
FROM t_account
WHERE Update_Timestamp > '2008-03-09 12:35:10.309000' AND Update_Timestamp
<= '2008-03-09 12:35:37.861000'
AND (Update_Id != '48012851-3aa4-9940-9ab4-b8333da6b45b' OR Update_Id IS
NULL)

1 result.

So my conclusion is that the NOT EQUAL operator doesn't match how it should
the NULL value field.
Is it a bug or a wanted behavior ?

--
Yann