public void Add(ProgressFactor factor) {
            _factors.Add(factor);
            factor.Tracker = this;

            _total = _factors.Sum(each => each.Weight*100);
            Updated();
        }
        public void Add(ProgressFactor factor)
        {
            _factors.Add(factor);
            factor.Tracker = this;

            _total = _factors.Sum(each => each.Weight * 100);
            Updated();
        }