Shared windows can be moved without having an impact on what others see. This is a big change that also allows you to move a window shared with you to another screen. The only limitation is that you can only share windows from one of your own screens at a time (like before).
Shared remote windows can be resized without having an impact on the size on the other end. That means that you can now simply drag the corner of a window shared with you to give it the perfect size.