If you have any problems with your dashboard for any reason, clicking on StopDashboard Widget will clear the memory of any dashboard activity. All you need to do to recall it again is press F12. That's about all there is to it. There are no preferences or options. The only problem you might have with it is if your Dashboard problems are serious enough, you might not even be able to click StopDashboard Widget.
StopDashboard Widget is a quick and effective way to clear your RAM if your dashboard is hogging it.