I would like to highlight (increase stroke thickness) a series when you hover over it in the legend.
To be able to do that I need access to the legend to series mapping.

Either by making the mapping protected so a derived class of Legend can access it.
protected Dictionary<Series.Series, OxyRect> SeriesPosMap { get; set; }

Or by providing a point to series getter function.
protected Series.Series? GetSeriesThatIsHit(ScreenPoint point)

Would either of these options be accepted in a pull request?
Any preference?