Mountain Lion always switches to previous application at wake up

Question

Since upgrading to Mountain Lion (from Snow Leopard), I have noticed that always when I wake up my MacBook Pro, a window from the previously active application is moved to the front.

What causes this? Can I turn this "feature" off?

Answer 1

Thanks Daniel Lawson for pointing to the solution:

The issue is cause by the 'require password after sleep or screen saver begins' option in the system security settings. If you turn this off, the issue disappears.