Googled various combinations of "taskbar" "window" "minimize" "focus" and some other keywords.
"System settings" -> "Multitasking" -> Looked through options for window behaviour found nothing relevant. Found no option that would remedy the situation. Right clicked taskbar -> check "Personalization" -> "Taskbar". What I want is for the window to minimize, as it did before the update. I now click the icon for the same window, still in focus. It restores itself to its previous size/position and takes focus, as expected and as wanted. I click on the icon for a minimized window. Let's say I have a number of applications running, with icons in the taskbar. I've reversed some of the changes but one persists and I can't seem to find where to fix it. After applying the anniversary update, Windows 10 decided it was okay to change various settings for me.