Redzar: not sure about what you are asking for, I guess I misunderstood - yes, setting the tracker template to null disables the tracker.
See also https://oxyplot.codeplex.com/discussions/454236 if you need to subscribe to the 'tracker changed' event
See also https://oxyplot.codeplex.com/discussions/454236 if you need to subscribe to the 'tracker changed' event