markerVisibility property

Whether marker should be visible or not when trackball is enabled.

The below values are applicable for this:

• TrackballVisibilityMode.auto - If the isVisible property in the series markerSettings is set to true, then the trackball marker will also be displayed for that particular series, else it will not be displayed.
• TrackballVisibilityMode.visible - Makes the trackball marker visible for all the series, irrespective of considering the isVisible property's value in the markerSettings.
• TrackballVisibilityMode.hidden - Hides the trackball marker for all the series.

Defaults to TrackballVisibilityMode.auto.

Also refer TrackballVisibilityMode.

late TrackballBehavior trackballBehavior;

void initState() {
  trackballBehavior = TrackballBehavior(
    enable: true,
    markerSettings: TrackballMarkerSettings(
      markerVisibility:  TrackballVisibilityMode.visible,
      width: 10
    )
  );
  super.initState();
}

Widget build(BuildContext context) {
  return SfCartesianChart(
    trackballBehavior: trackballBehavior
  );
}