Hi Kamen,
By default Fancytooltip displayed series name and chart point as a tooltip.
For more details please refer the following method in your source project.
private string GetTextForToolTip( ChartSeries series, ChartPoint pt )--[Chart.Base\ToolBar\ChartFancyToolTipController.cs.]
Please have a look at the attached sample.
http://websamples.syncfusion.com/samples/Chart.Windows/F62283/main.htmThe above sample displayed Seriesname and chartpoint values as a Fancytooltip.
Please let me know if you have any more queries.
Regards,
Rashidha.