In the Coffee Machine example, if you try to resize the application window, the content is not properly responsive. If you make the window smaller it will crop the contents. If you make the window larger it will not expand the contents, but rather add a black background to the bottom, and include another state of the application to the right. In full screen, the black background and the other state is the most visible.

Example images:

The default window size before any changes.

Making the application window smaller.

Making the application window larger, with visible black background.

Full screen.