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Returns a ChartLine object representing the series lines from the main pie chart to the secondary chart in a bar of pie or pie of pie chart.

 public ChartLine BopPopSeriesLines{ get; }

Public ReadOnly Property BopPopSeriesLines() As ChartLine

This defaults to a ChartLine with the properties set as below, when creating a new Bar of Pie or Pie of Pie series:
Visible = true,
Style = ChartLine.LineStyle.Solid,
Weight = ChartLine.LineWeight.Narrow for xlsx, ChartLine.LineWeight.Hair for xls,
Color = Color.SystemColor.AutomaticLine

This property is linked for series in the same group. See SettingsPieDoughnut for more information on how linking works.
For series that are not Bar Of Pie or Pie of Pie series, the in-code behavior is undefined, but changing the properties on this ChartLine will have no effect on the output.