When grading student work, the swipe from student4.pdf to student5.pdf causes the app to crash. There is no way to advance to student5 and beyond. It also is occurring in another assignment set, so it is not the pdf causing the hang-up. I have updated the operating system, deleted and reloaded the app—nothing has fixed it. I can still access the work via the web, but the annotation function there is less fluid than using my stylus on the iPad— so time consuming and location restrictive.