I am having the same problem with wandering when I click a toll menu on a 2013 macbook pro, OS 10.12.6 and SU 2017
I thought it might be my apple magic mouse (the electrostatic touch of the ouse) so I switched to a Logitech USB mouse. Unfortunately, same problem continues. Just upgraded to the latest version of 2017 and so far no trouble. We’ll see if that lasts.