How can I deactivate automatic login to FamilySearch Family Tree?

In FamilySearch Central the first row under "Task to Do" is the logout link. As soon as you log out it will let you log back in again as a different person. 

On the FamilySearch Login screen, that will appear, you can make adjustments to your settings for your login to be remembered/or not, by adding or removing the below check-marks.

• Remember my sign in and password
• Automatically log in (bypass this screen)

You would need to at least login once with the new settings for it to be remembered later.