I have a 12.9 iPad Pro on iOS 10. It is mostly a great experience and improvement, even coming from iPad Air 2. However, one feature leaves me constantly frustrated: split-screen is side-by-side only. I am so baffled that Apple didn't implement split screen for top/bottom use while holding the ipad in portrait. Imagine watching YouTube lectures while taking notes... a movie while browsing the web or checking email... Facebook or messages while watching the game... All of these scenarios would offer a full HD video (on the 12.9, and standard HD on other iPads) at the top of the screen while allowing an iPad mini equivalent sized app in landscape orientation below. Sure we can do those things now, but there are so many scenarios that are not ideal in side-by-side. At best we can do the pop-out video that is a small window in a corner of the screen. (And I don't think YouTube app even allows this yet, right?). I'd really like to know why we don't have top/bottom split screen on iPad. Does anyone have some insight into this?