Screensaver question

[tttaff]

I'm running the Folding@Home Windows client v5.03, and have the screensaver set to run after 15 minutes. I also have the "Run Core only when screensaver is active" checkbox checked, but the core runs all the time, not just when the screensaver is active (the system tray icon shows "F@H: Working" and is taking up CPU time). How can I get this to remain idle and work only when the screensaver is active?

Thanks...