How to edit the page 0 "template" in APEX 4.2

Question

I have an application that has been upgraded to APEX 4.2.  On page 0, when I try to move an existing region to Region Position 8 I get an error: "This region position is not in your page template".  Looking at the page definition (component view) I can see the name of the template associated with page 0, so I edited that page template and added #REGION_POSITION_08#, but still I get the same error message.  So I thought perhaps I would change page 0 to use a different template, but Edit Page does not show the page template at all for page 0. 
So I suspect that page 0 is no longer supposed to have a template at all, yet my upgraded application does (sort of) and I can't change it.  Any ideas?

Answer 1

Dear Paul,
I used the login_table for my login page,
which has only two fields username and password as like login screen, in my appliction in the change password page
I used the another table called Update_user
which has four fields,
1.username
2.current_password
3.New_password
4.Retye
and the change password page contains this exact same 4 fields from this Table,
whenever the users entering the 4 fields and if they click the create/update button the data will be stored in the Update_Table
and the password field in the Login_table will be updated based on the following trigger,
   create or replace TRIGGER  trg1
before insert on update_user
referencing old as old new as new
for each row
begin
    update login_table set password= :new.retype where username=:new.username;
end;
       As you said I tried that :APP_USER and I made the username column as read only,
When the values inserted except the username other 3 values inserted into the update_user table and the login_table not updated so the password also not changed,
Is there any other way to directly upadte the password in the Login_table without going for another Table?
Please Give some suggestion.
Thank you,
regards,
Gurujothi