I finally upgraded to El Cap a few nights ago. I just tried looking at curves in full screen mode and everything seems to scale just fine, but it is hard to switch from one curve to the other when in the new full screen mode. I am pretty sure there is some gesture with the magical mystery trackpads and mighty mice that will allow you to swipe through the open fullscreen windows but I don't have those—i just use the old wired keyboard and a waco tablet. The way around this is pretty easy though. If you click the green fullscreen button while holding down the option key it maximizes the window like the system did before things went to full screen mode. Then you can use the command+~key to toggle through the open widows just like any other application.