I have a tracker in which I have initially created users as 
admin. It would be nice if users could subsequently 
modify their usernames via their 'details' menu.
However, when this is attempted the following error 
occurs (minus the long python traceback):

    Templating Error
    exceptions.KeyError: 'No key (username)   
value "<current_username>" for
 "user"'

 where <current_username> is the user's existing 
username.

>This is the result of the hyperdb attempting to journal 
>the changes to the user's record. Each journal entry 
>records the userid of the user making the change. As a 
>result of a historical decision, we remember the 
>*name* of the current user when the hyperdb is 
>opened, not the userid. When the journal entry is 
>written, we look up the userid. Hence when your user's 
>details are changed, and we try to write the journal 
>entry, the username we recorded doesn't exist any 
>more -- though when you do it as admin, everything's 
>obviously OK.
>
>Please file a bug report - this should be fixable.
>
>   Richard