Is it just me but some of the basic things like moving objects around or moving a couple of objects around is sketchy in rhino V8. For example, when I am moving a basic cube while holding the alt key I can move it but rhino makes the copy where it wants. Not sure if it is a gumball issue or if it is a grid snap issue. Sorry if this has been posted before I could not find the topic. 
Do you have snappy dragging enabled in the Gumball? Not seeing any issues in a quick test with these settings.
No I have Smooth Dragging. Never saw that before.
Snappy dragging along with SmartTrack makes for quick work. Enjoy 