Just for fun, holding the right mouse button down does not work a menu the same way it does when holding the left-mouse button down. To work the right mouse button menu's, you must release the button before the contextual menu will appear. Which is inconsistent with all other menus. This will close the application, but of course it is called end task. Like everything in Windows there are rules, and then the exceptions.
Nothing seems to be a rule.
This is bad interface. These are only the ways of closing a Window that I know of. I'm sure that there are more. But that is still a way for them to adjust to a bad interface. The problem is that most people accept the idiocy of interface, and loss of productivity, without blaming Microsoft.