Chart.SeriesNameLevel (PowerPoint)

Returns or sets an XlSeriesNameLevel constant that specifies the source level of the series names.

Possible Values are xlSeriesNameLevelAll - Sets series names to all series name levels within range on the chart. The default, xlSeriesNameLevelCustom - Indicates literal data in the series names, xlSeriesNameLevelNone - Sets no series names in the chart.
ActiveWindow.RangeFromPoint.Chart.SeriesNameLevel = xlSeriesNameLevelAll