Hi Manal,
Yes that's right - the paint order is controlled from the position of the series in the chart collection. The first series appears on top of the other series and so on. In order to change the z order of the series you need to change its place in the series collection. We may consider adding a z order property for the series. Let us know if you meet any problems or have any questions.

Best Regards,
Nevron Support Team

Hi Manal,
Please elaborate on this question. The following code shows how to create a chart with two high low series:

   NCartesianChart chart = (NCartesianChart)nChartControl1.Charts[0];
   
   // set a chart title
   NLabel title = nChartControl1.Labels.AddHeader("2D High Low Chart");
   title.TextStyle.FontStyle = new NFontStyle("Times New Roman", 18, FontStyle.Italic);
   title.TextStyle.FillStyle = new NColorFillStyle(Color.Gray);

   // add a High-Low series
   Random rand = new Random();
   
   NHighLowSeries highLow1 = (NHighLowSeries)chart.Series.Add(SeriesType.HighLow);
   highLow1.Name = "High-Low 1";
   highLow1.HighFillStyle = new NColorFillStyle(Color.Gray);
   highLow1.LowFillStyle = new NColorFillStyle(Color.DarkOrange);
   highLow1.DataLabelStyle.Visible = false;

   highLow1.ClearDataPoints();

    
   for (int i = 0; i < 20; i++)
   {
    double d1 = Math.Log(i + 1) + 0.1 * rand.NextDouble();
    double d2 = d1 + Math.Cos(0.33 * i) + 0.1 * rand.NextDouble();

    highLow1.HighValues.Add(d1);
    highLow1.LowValues.Add(d2);
   }

   // add a High-Low series
   NHighLowSeries highLow2 = (NHighLowSeries)chart.Series.Add(SeriesType.HighLow);
   highLow2.Name = "High-Low 2";
   highLow2.HighFillStyle = new NColorFillStyle(Color.Red);
   highLow2.LowFillStyle = new NColorFillStyle(Color.Green);
   highLow2.DataLabelStyle.Visible = false;

   highLow2.ClearDataPoints();

   for (int i = 0; i < 20; i++)
   {
    double d1 = Math.Log(i + 1) + 0.5 * rand.NextDouble();
    double d2 = d1 + Math.Cos(0.33 * i) + 0.5 * rand.NextDouble();

    highLow2.HighValues.Add(d1);
    highLow2.LowValues.Add(d2);
   }

Generally you can mix an unlimited number of series in a chart.

Best Regards,
Nevron Support Team