Contemporary UI interfaces, not just EndNote 20, has this horrible trend of enlarging everything and creating lots of empty spaces. This makes sense if the UI is intended to be a touch interface, but for one in which we navigate by mouse/trackpad, this is terribly wasteful. The irony is that today we have much larger monitors than 20 years ago, but because of the inefficient use of space, our displays contain just about as much information as they did in the past.
EndNote UI, as well as other programs, should aim to display information density with clarity and ease of use.