This sample illustrates the empty point functionality in chart series. The mode of empty point can be changed by using Empty Point Mode in property panel.
In this example, you can see how to render and configure the empty points. You can use border,
fill, mode properties to customize the empty points.
Tooltip is enabled in this example, to see the tooltip in action, hover a point or tap on a point in touch enabled devices.
More information on the empty points can be found in this documentation section.