Hello Experts,

I have a NHeatMapSeries which looks like:

So far so good. But now I want to add a line with a anchored CallOut-Label at y=5:

   NLineSeries line = (NLineSeries)_oChart.Series.Add(SeriesType.Line);
    line.Name = "ReferenceLine";
    line.UseXValues = true;
    line.MarkerStyle.Visible = false;
    line.DataLabelStyle.Visible = false;
    line.InflateMargins = false;
    line.BorderStyle.Color = oLine.Color;
    line.BorderStyle.Width = new NLength(oLine.Thickness, NPointGraphicsUnit.Point);
    line.Values.AddRange(oLine.YValues);
line.XValues.AddRange(oLine.XValues);
     // Create a rounded rect callout 
      NRectangularCallout m_RectangularCallout = new NRectangularCallout();
      int iLabelPos = 8; 
     ...
     // Anchor the callout to data point #0 of the line series
      NDataPointAnchor anchor = new NDataPointAnchor(line, 1, ContentAlignment.MiddleCenter, StringAlignment.Center);
      m_RectangularCallout.Anchor = anchor;
      m_RectangularCallout.AlwaysInsideParent = true; 
_NevronChart.Panels.Add(m_RectangularCallout);

Result: The Callout label is plotted (see picture lower right: label with green back colour)- but no line is plotted. The very same approach does work for Point- and Line plots though. What must be done to make it working with NHeatMapSeries ?

Thanks for the help,
best regards,
Joern