1) Open family page in FSDemo
2) Open pedigree editor
3) Use scroll trackpad function to zoom in and out of the pedigree (usually accomplished by moving two fingers up and down on the trackpad simultaneously.)
Finger movements of less than 1 mm will zoom the pedigree fully in or out, and it is very difficult to zoom to any size in between. On the other hand, using a mouse scroll wheel allows one to land on every single zoom node.
Zoom sensitivity in response to trackpad movements should be decreased.