Firefox 3 and scroll wheel

[stan]

After upgrading to Firefox 3 I have observed some truly annoying behavior.
When I use the scroll wheel on the mouse to scroll up, if I scroll to far
the browser goes back to previous sites in history. I find this really
annoying. How can I turn this "feature" off?

-- 
One of the main causes of the fall of the roman empire was that, lacking
zero, they had no way to indicate successful termination of their C
programs.