Q: My PDFs are all scrolling backwards on my Mac. What happened?
A: Some users on Mac OSX Lion are surprised about reversed scrolling in PDF Studio.  Mac OSX Lion has introduced “Natural scrolling” and reversed the typical mouse scrolling direction: with reverse scrolling, scrolling down on the mouse moves content in the window in an upward direction, much like scrolling on a mobile phone or tablet. It is possible to switch your mouse gesture back to Snow Leopard’s behavior. In Lion, go to System Preferences > Mouse > and remove the tick from “Scroll direction: natural”.