The Annotation will be displayed below the chart grid lines, bands, and axes.
remarks
Use this for custom background behind the chart.
BelowChart
BelowChart: = "BelowChart"
The Annotation will be displayed below the chart series and grid.
remarks
Doesn't work with SVG (Custom) annotations.
Use this for watermarks, e.g. showing an image or text behind the chart.
The Grid lines and Axis Bands will show over the annotation,
so consider setting AxisCore.axisBandsFill to a semi-transparent color to avoid this.
Defines the layer where Annotations are drawn when added to the SciChartSurface.annotations collection