ActiveChart Property
Returns a Chart object that represents the active chart (either an embedded chart or a chart sheet). An embedded chart is considered active when it's either selected or activated. When no chart is active, this property returns Nothing. Read-only.
Remarks
If you don't specify an object qualifier, this property returns the active chart in the active workbook.
Example
This example turns on the legend for the active chart.
ActiveChart.HasLegend = True