Window Preferences: changes to not take effect

[Chris Stankevitz]

FreeBSD 8.1-RC1, GNOME 2.30.0

System | Preferences | Windows | "Select windows when the mouse moves over them"

When I check the above box, a checkmark appears; however, the windows do not gain focus when I move my mouse over them.  Additionally, after closing and re-opening this preferences window, the checkmark is still checked.

Q: Why doesn't checking this box make the window focus follow the mouse cursor?

Thank you,

Chris