lineColor property
Color of the track line.
Defaults to null.
late TrackballBehavior trackballBehavior;
void initState() {
  trackballBehavior = TrackballBehavior(
    enable: true,
    lineColor: Colors.red
  );
  super.initState();
}
Widget build(BuildContext context) {
  return SfCartesianChart(
    trackballBehavior: trackballBehavior
  );
}
Implementation
final Color? lineColor;