problem of revoking global privileges

[Zhe Wang]

Hi, all,
   I am having trouble of revoking global privileges. Your help will be 
greatly appreciated.

   I created a user called "dummy" identified by password "dummy" by :
grant usage on *.* to 'dummy'@'%' identified by 'dummy';
    Then I did:
mysql> show grants for dummy;
+-----------------------------------------------------------------------------+
| Grants for 
[EMAIL PROTECTED]                                                          |
+-----------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'dummy'@'%' IDENTIFIED BY PASSWORD 
'710e7e2213ba44ca' |
+-----------------------------------------------------------------------------+

     It looked fine. However strange thing happened after I did
flush privileges;
     show grants for dummy; would give me:
+----------------------------------------------------------------------------------------------------------------------------+
| Grants for 
[EMAIL PROTECTED]                                                                                                         
|
+----------------------------------------------------------------------------------------------------------------------------+
| GRANT SHOW DATABASES, CREATE TEMPORARY TABLES, LOCK TABLES ON *.* TO 
'dummy'@'%' IDENTIFIED BY PASSWORD '710e7e2213ba44ca' |
+----------------------------------------------------------------------------------------------------------------------------+

      I don't understand how this could happen. Are the privileges for 
SHOW DATABASES, CREATE TEMPORARY TABLES, LOCK TABLES ON *.* default 
global privileges? Is there a way to turn this off so the user dummy has 
no global privileges at all?

        I am using MySQL 4.0.20 on Solaris.
        Thanks in advance for your help.
Regards,
Zhe