I'm using v 4.0.3, and every so often, on clicking a link, I find that the window which opens has no scroll bars even though it is too big to fit on one screen. The problem is easily avoided by opening a new window of course, but is this something which anyone else has observed? It is a problem which I have also found on earlier versions of Safari.
Is this something to do with monitor resolution. Perhaps the scroll bars are there but just not visible on the screen. Try a different resolution as an experiment.