curveNumber when using groupby transform

Hi,

When using a groupby transform, what does the “curveNumber” property represents?

I’m trying to sync the “hover” event of a plot that uses groupby but the curveNumber I get from the event doesn’t work. This is the rough idea:

graph.on('plotly_hover', function(click_data){
var hover = click_data.points.map(point=>{
	return {curveNumber: point.curveNumber, pointNumber: point.pointNumber};
});
Plotly.Fx.hover(other, hover);
});

With this code, point.curveNumber is zero for all groups, and it looks like that is not what the hover method expects. I managed to get the correct data from point.fullData._expandedIndex

graph.on('plotly_hover', function(click_data){
var hover = click_data.points.map(point=>{
	return {curveNumber: point.fullData._expandedIndex, pointNumber: point.pointNumber};
});
Plotly.Fx.hover(other, hover);
});

Is there another property that exposes this more clearly?

Here is a pen to show the problem and current solution.

Not at the moment unfortunately.

Not job digging through to find

+1