Declaration: ChartBook.Charts[].ClassVisible[cnum: byte]: boolean;
The array property ClassVisible determines whether any items of the class cnum are displayed or not. The parameter cnum may take any value between 0 and 254. The value of 255 is reserved as a place holder for all classes.

This property may be used to temporarily "switch off" parts of the data in a chart. Please note that ClassVisible only affects the display of the data. Items which have been made invisible can be processed like any other visible items.