C# chart object not applying negative points on xaxis

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C#

chart

Trying to implement a simple line chart in C# (2013) that applies a series of negative to positive values on both the X and Y axis. However the chart does not accept the negative Series points for the X axis. The -100 to +100 values are properly displayed on the X axis, but the -50 "Y" value originates at the "0" X axis value position. What am I doing wrong?

The C# code:

public void DrawSampleChart()
{
    Graph.Chart chart = new Graph.Chart();
    chart.Dock = DockStyle.Fill;
    Main.ChartPanel.Controls.Clear();
    Main.ChartPanel.Controls.Add(chart);
    chart.ChartAreas.Add(new Graph.ChartArea());

    //  Define the horizontal ("X") axis attributes
    chart.ChartAreas[0].AxisX.Minimum = -100.0;
    chart.ChartAreas[0].AxisX.Maximum = 100.0;
    chart.ChartAreas[0].AxisX.Interval = 10;

    //  Define the vertical ("Y") axis attributes
    chart.ChartAreas[0].AxisY.Minimum = -100;
    chart.ChartAreas[0].AxisY.Maximum = 100;
    chart.ChartAreas[0].AxisY.Interval = 10;

    //  Add sample series
    Graph.Series series = new Graph.Series("Series1");
    series.ChartType = Graph.SeriesChartType.Line;
    for (int n = -50; n <= 50; n++)
        series.Points.Add(n, n);
    chart.Series.Add(series);
}

What I have tried:

The above code compiles and executes on Visual Studio 2013.