Currently, RadChartView offers exporting to a Bitmap in one of the following formats: https://docs.microsoft.com/en-us/dotnet/api/system.drawing.imaging.imageformat?view=netframework-4.8

It would be nice to have export functionality to  a vector image.

Add Point and Figure Series to RadChartView

The Step Line chart type is similar to the Line chart type, but it does not use the shortest distance to connect two data points. Instead, this chart type uses vertical and horizontal lines to connect the data points in a series forming a step-like progression.

https://demos.telerik.com/kendo-ui/radar-charts/radar-column

The attached proejct shows a sample implementation.

When one adds data points with negative and positive values, the negative ones should go below the 0, for example, with the following data:

AreaSeries areaSeries = new AreaSeries();
areaSeries.DataPoints.Add(new CategoricalDataPoint(5, "Jan"));
areaSeries.DataPoints.Add(new CategoricalDataPoint(-10, "Apr"));

Resolution: 
To use the functionality one should set the StartPositionAxis and StartPositionValue properties of an axis. The first property is the axis along which the current axis will be aligned. The second is the value where the current axis should be positioned.
Here is a sample code: 
AreaSeries areaSeries = new AreaSeries();
areaSeries.DataPoints.Add(new CategoricalDataPoint(13, "Jan"));
areaSeries.DataPoints.Add(new CategoricalDataPoint(20, "Apr"));
areaSeries.DataPoints.Add(new CategoricalDataPoint(-15, "Jul"));
areaSeries.DataPoints.Add(new CategoricalDataPoint(16, "Oct"));
this.radChartView1.Series.Add(areaSeries);

areaSeries.HorizontalAxis.StartPositionAxis = areaSeries.VerticalAxis;
areaSeries.HorizontalAxis.StartPositionValue = 0; 

Add the ability a user to be able to use a Custom DashStyle in the following scenario:

this.Chart.ShowLegend = true;
this.Chart.Series.Add(new LineSeries() { LegendTitle = "DDDD" });
this.Chart.ChartElement.LegendElement.Items[0].Element.BorderDashStyle = System.Drawing.Drawing2D.DashStyle.Custom;

for (int i = 0; i < 10; i++)
{
    this.Chart.Series[0].DataPoints.Add(i);
}

The following article describes how to use a Custom DashStyle: How to: Draw a Custom Dashed Line

How can I achieve the same behaviour as with the obsolete RadChart plotting the area between the maxima of a sine. 

Introduce gantt like series as in RadChart: http://docs.telerik.com/devtools/winforms/chart/understanding-radchart-types/gantt-charts 

so that Y increases as you move down the screen. (Even) microsoft chart component supports this. 

ADD. RadChartView - add waterfall series type.

Gets the range that is actually visible on the plot area when the chart is zoomed in.

To reproduce:

AreaSeries areaSeries = new AreaSeries();
areaSeries.DataPoints.Add(new CategoricalDataPoint(13, "Jan"));
areaSeries.DataPoints.Add(new CategoricalDataPoint(20, "Apr"));
areaSeries.DataPoints.Add(new CategoricalDataPoint(15, "Jul"));
areaSeries.DataPoints.Add(new CategoricalDataPoint(16, "Oct"));
this.radChartView1.Series.Add(areaSeries); 

areaSeries.BackColor = Color.Transparent;

areaSeries.CombineMode = ChartSeriesCombineMode.Stack;
AreaSeries areaSeries2 = new AreaSeries();
areaSeries2.DataPoints.Add(new CategoricalDataPoint(15, "Jan"));
areaSeries2.DataPoints.Add(new CategoricalDataPoint(25, "Apr"));
areaSeries2.DataPoints.Add(new CategoricalDataPoint(27, "Jul"));
areaSeries2.DataPoints.Add(new CategoricalDataPoint(18, "Oct"));
this.radChartView1.Series.Add(areaSeries2);
areaSeries2.CombineMode = ChartSeriesCombineMode.Stack;

 The area underneath the transparent one shouldn't be displayed in this case because they are stacked.  There is no area underneath the bottom layer to display. They are each STACKED on top of each other, they should not be layered in front of each other.

Until the feature gets implemented please use the suggested solution here: http://www.telerik.com/support/kb/winforms/details/integrating-panzoom-trackball-and-lassozoom-controllers-in-radchartview

Telerik.Charting namespace exist in the WinForms and the WFP assemblies and one cannot reference both in a single project.