To reproduce:

public Form1()
{
    InitializeComponent();

    this.radChartView1.ShowPanZoom = true;
    Random rand = new Random();
    this.radChartView1.AreaType = ChartAreaType.Polar;
    for (int i = 0; i < 85; i++)
    {
        RadarLineSeries radarPointSeries = new RadarLineSeries();
        for (int j = 0; j < 8; j++)
        {
            radarPointSeries.DataPoints.Add(new CategoricalDataPoint(rand.Next(1, 100), "X" + j));
        }
        this.radChartView1.Series.Add(radarPointSeries);
    }
}

Workaround: set the ShowPanZoom property after the chart is populated with data.