in src/behavior.ts [39:53]
export function getFillOpacity(
dot: LineDotPoint,
selected: boolean,
highlight: boolean,
hasSelection: boolean,
hasPartialHighlights: boolean,
): number {
if ((hasPartialHighlights && !highlight) || (hasSelection && !selected)) {
const opacity: number = dot.opacity - DimmedOpacity;
return opacity < MinOpacity ? MinOpacity : opacity;
}
return dot.opacity;
}