There are know issues with Kivy Pi and the mouse pointer. The thread mentioned above addresses it. I did lots of testing on the Pi. As documented with a Pi3 and the Pi foundation touch display all works. There are a few folks here that got it working on a Pi without the display. I ended up using Ubuntu Mate and found it to be stable, reliable and repeatable. They don’t have an image for 3B+ and they are planing on porting V18 next in about 4 moths is the ETA.