MovingAverageIndicator doesn't recalculate its data points when a new item is added in its ItemsSource at runtime

Workaround:
To update the data points of the indicator reset its Period property when a new item is added in the ItemsSource. For example:

// add new item
var indicator = chart.Indicators[0] as MovingAverageIndicator;
var period = indicator.Period;
indicator.Period = 0;
indicator.Period = period;