Is there a way to control how long a tooltip stays visible?

I have some tooltips that are rather lengthy, and which take a while to read. My problem is, after a few short seconds, the tooltip vaqnishes. The user then has to move the mouse around to get the tooltip to reappear.

Is there a setting I can modify to lengthen the time the tooltip stayus visible? If so, where can I get at it?

Thanks,

-Steve