Deleted user persists in Login Window Preferences Security tab

The name of a deleted user continues to be available (selectable) in the Login Window Preferences | Security tab, in the drop-down menu associated with "Enable automatic Login". This only happens when the user that is deleted is remains selected for automatic login. The deleted user cannot authenticate to the computer via this defect, so I do not detect any security risk to the computer.

Defect tested and duplicated in:
Ubuntu 7.04 (Feisty Fawn)
Ubuntu 7.10 pre-release (Gutsy Gabon)

Steps to Reproduce:
1. Create a new user (using default settings)
1b. System (menu) >> Administration >> Users and Groups
1c. Select the button named, "Add User"
1d. Add a username, a real name and a password and click the "OK" button. For example, create a user named "tester"
1e. Close the "User Settings" window

2. Enable Automatic Login
2b. System (menu) >> Administration >> Login Window
2c. Go to the tab named, "Security"
2d. Check the box next to "Enable Automatic Login"
2e. In the drop-down list next to "User:" select the name of the new user you created. For example, I created a user named "tester"
2f. Close the window by clicking on the button named "Close"

3. Delete the new user
3b. System (menu) >> Administration >> Users and Groups
3c. Select the username of the new user. For example, I selected the user named, "tester"
3d. Click the button named, "Delete"

4. Defect: This user is not deleted from the Login Window Preferences Security Tab.
4b. System (menu) >> Administration >> Login Window
4c. Go to the tab named, "Security"
4d. You may observe the deleted user name is still found in the drop-list next to "User:"
Un-checking the box named "Enable Automatic Login" does not remove the username
Rebooting does not remove the username.

Selecting another, active user, and closing the Login Window Preferences window *does* fix the problem. After this, the delete username may not be found in the drop-down menu.