I had this question after viewing Open applications in Windows 10 keep minimizing
Thought this was cleared up, but still has an issue. For example, I open web sites A, B, C, D and E in Firefox. I can click the icon in the tray and I get the four small views. I can mouse over them and get full screen shots. I can click on the small view (not the full screen, but that's OK) and now I am focused on what I clicked into. But now I also open Word and have two files, Word A and Word B. I can switch between them as before, but I cannot go to the Firefox sets. I get the small previews and full screen, but as soon as the mouse comes off the small preview it and the full screen version disappear. I have fiddled with the various settings for whether or not to show the task bar.