Z offset option on motion on vicky does not seem to do anything

[martinpirringer]

Create a gcode file (calibration box is ok - maybe enlarge to get bigger first layer and slice first layer only)
Start it on the vicky
change z -offset under control - motion - no effect
or
alternately
change z-offset before hitting start print - no effect.
This makes dialing in difficult even with a computer connected as each time the z-offset is changed everything needs to be re-sliced. Being the fact that on a pulse the z-offset changes frequently it is quite annoying