By default Buttons stay selected after you click them. This confused me, and many other users. It is behaviour that regular buttons in your OS definitely dont share. For regular mouse navigation this is extremely unexpected behaviour, though it could be useful for console games, or keyboard navigation.
My change will only keep it selected when keyboard navigation is enabled. This makes sense, because its what you expect on keyboard navigation, and not when there is no keyboard navigation.
It is possible to get this behaviour currently by setting Navigation to None on all selectables. This is quite counterintuitive, i have no clue what these names mean. I guess its KeyboardNavigation? Why is this an option per UI element, and not something globally?
If you ask me, Selected and Highlighted should definitely have a different visual state too, and this change should be default.