[Google-Desktop] Have to wait for idle?

I apologize in advance for the newbie questions, but I'm just now
trying out Google Desktop (after trying but not liking MSN Toolbar),
and have just started my first indexing. Right now it's sitting there
saying it will only index when idle. Is there any way to get it to
index in the background while I work?

And if not, what does it define as "idle"? How long do I have to be
idle before it starts searching again?

Thanks,

t.