I keep reading about Mail and Notes serving up a three-panel display when you have your iPad Pro in landscape. How do you get this? I can't make it work. A lot of the descriptions say to click an icon in the top left-hand corner, but that just toggles between 1- and 2-panel display. Do I need to have multiple folders to get this to work in Notes? Do I need to have multiple email accounts to get this to work in Mail? I can't figure it out.