in src/behavior.ts [54:63]
public renderSelection(hasSelection: boolean) {
let options = this.options;
let hasHighlights = options.hasHighlights;
options.valueRects.style("opacity", (d: BarValueRect) =>
BulletWebBehavior.getFillOpacity(d.selected, d.highlight, !d.highlight && hasSelection, !d.selected && hasHighlights));
options.rects.style("opacity", (d: BarRect) =>
BulletWebBehavior.getFillOpacity(d.selected, d.highlight, !d.highlight && hasSelection, !d.selected && hasHighlights));
}