BCGControlBar Pro for MFC
void CBCGPChartLegendVisualObject::SetScrollStep ( double  dblStep)

Specifies constant scroll step

If you don't specify scroll step it will be calculated automatically based on legend size. The default value is 0 (automatic calculation). You can also override OnCalcScrollStep() and return a desired value based on some other conditions.

dblStepspecifies new scroll step in device units