code: function scroll (event) {
      if (!ctrl.shouldPaginate) return;
      event.preventDefault();
      if (event.deltaY) {
        ctrl.offsetLeft = fixOffset(ctrl.offsetLeft + event.deltaY);
      } else if (event.deltaX) {
        ctrl.offsetLeft = fixOffset(ctrl.offsetLeft + event.deltaX);
      }
    }
docs: When pagination is on, this makes sure the selected index is in view.
  @param {WheelEvent} event