On closer inspection (ie, RTFM) it looks like this is expected behaviour, which is a shame as it's not very helpful to us laptop users to have this big strip of dead space sat in the middle of the screen. I hope GUI resizing will be added in a furure update - the way my other Arturia synths (Prophet V, Modular V, Jupiter 8V and ARP 2600) allow different sizes and sections of the GUI to be shown is really great when working on a laptop.