Why can I stop my Twitch app only with Alt-F4 or the Taskmanager and not just with the X?

When I press the X, it gives the same effect as when I press that.

Many programs nowadays only minimize themselves to the toolbar and are not closed directly.

As a rule, it is sufficient to search for the icon of the application and to select the exit command by right-clicking on it.

At the top right there should be such an arrow. If you press it opens a small menu at the bottom should be finished.