Not able to see the full calibration screen?
I ran into this issue and wanted to share my solution. Below you can see the screen I got the first time I tried calibrating.
As you can see, the option to Define Zero is hidden below the bottom of the visible area. I could not scroll further down to see the button. I tried changing the viewing scale in Windows, but that did not work.
I asked on the Facebook group and several responded to change the screen resolution. I tried that and it did fix the problem. My laptop has a high resolution screen, by changing it to 1920x1080 (standard HD resolution), I was able to see the full window and all of the options.