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I later discovered that the problem occurred because my zoom (screen size) in chrome was set to 110%. When I reset it to 100% the scrollbar re-appeared. Still not sure what's wrong with IE but I can work on Chrome now. Nevertheless, the issue should be addressed in Chrome with either a user message or correction to the program so it doesn't happen to some other unenlightened author. My zoom often changes unintentionally when I swipe my finger across the pad. I haven't yet figured out how to turn that off.