Created Issue: Chart throws InvalidOperationException when last StackedAreaSeries item removed [10547]

If a Chart contains both a LineSeries and a StackedAreaSeries, an InvalidOperationException (Sequence contains no elements) exception is thrown when the last StackedAreaSeries.SeriesDefinitions child is programmatically removed.

I've attached a simple project that demonstrates the bug. You just have to click the Add and then the Remove button.