This isn't actually a Sierra issue, since I think it occurred in earlier versions as well. Say I've got three different Power Point presentations open, each in full screen, thus on its own desktop. Now, say I'm on my main desktop, with another application than Power Point active, and I want to go to a specific PP document. I invoke Mission Control, click on the document/desktop I want, I get taken momentarily to the right desktop, but then it usually immediately changes to another desktop and I have to invoke Mission Control again to choose the right one. However, if I'm already in Power Point, the problem doesn't exist. I find this behaviour weird. Any help?