in src/behavior.ts [74:86]
public renderSelection(hasSelection: boolean): void {
const hasHighlights: boolean = this.interactivityService.hasSelection();
this.selection.style("opacity", (stackedSeries: StreamGraphSeries) => {
const series = this.series[(<any>stackedSeries).index];
return getFillOpacity(
series.selected,
series.highlight,
!series.highlight && hasSelection,
!series.selected && hasHighlights);
});
}