This .NET class wraps the AcPlPlotFactory::PreviewEngineFlags ObjectARX class. It describes the plot preview functionality.

Public Enum PreviewEngineFlags
  NextSheet = 2
  Plot = 1
  PreviousSheet = 4
End Enum

public enum PreviewEngineFlags {
  NextSheet = 2,
  Plot = 1,
  PreviousSheet = 4
}