Since downloading 4.0, I've had lots of problems with page loading, Trackpad gestures, scrolling. having to click a new page to make it active, pointer does strange things on any page and a host of other minor but none the less irritating issues. I've had to revert back to 3.6.16 to get the browser to work again. Sorry but I've gone back to using Safari as my default browser until these issues with 4.0 can be resolved.