code: function(){
      var prev = this.prevHit,
          octx = this.octx,
          plotOffset = this.plotOffset;
      octx.save();
      octx.translate(plotOffset.left, plotOffset.top);
      if (prev) {
        if (!this.hit.executeOnType(prev.series, 'clearHit', this.prevHit)) {
          // TODO fix this (points) should move to general testable graph mixin
          var
            s = prev.series,
            lw = (s.points ? s.points.lineWidth : 1);
            offset = (s.points.hitRadius || s.points.radius || s.mouse.radius) + lw;
          octx.clearRect(
            prev.xaxis.d2p(prev.x) - offset,
            prev.yaxis.d2p(prev.y) - offset,
            offset*2,
            offset*2
          );
        }
        D.hide(this.mouseTrack);
        this.prevHit = null;
      }
      octx.restore();
    }
docs: Removes the mouse tracking point from the overlay.