about authentication in kde system setup tool

[Harry Putnam <reader@newsguy.com>]

Running wheezy

On a recently installed kde desktop environment, I'm getting confused
about being prompted when attempting to make certain changes.

I get a prompt that is about authentication.  A drop down list says 
`Select user', however my user that I'm logged in as is not there, nor
is root.  And yet I cannot continue without making a selection.

I don't understand what is expected of me there.  Surely I would not
want to select another user to have permission to alter my desktop.

Here is a sequence:

>From main menu/system settings/ Login screen/
In the font selector use `choose' button to change font and size/
Say `OK' then press `apply', at that point an authentication dialog 
pops up:

Administrator authorization is 
required to change the login
Manager settings.

An application is attempting to perform an
action that requires privileges
Authentication is required to perform this
action

-------        ---------       ---=---       ---------      -------- 

Then a dropdown list that says `select user' when I drop the list
down none of them are my user, nor root.

How is that supposed to work?