Declaration: ChartBook.Charts[].ActiveLayer: integer;
The property ActiveLayer controls the currently active layer and may assume values between 1 and 16. In general, drawing elements are always drawn on the currently active layer (without regard to the visibility of the active layer, see property LayerVisible). In addition, the grid of a chart is always corresponding to the coordinate system of the active layer. Thus switching the active layer changes the grid.

Hint 1: In order to affect all layers when interactive panning and zooming is enabled (property MouseAction = maPan, maZoom, ....) you have to configure the array property MouseAffectsLayer accordingly.