TcxGrid: dont have event for the "web-style" row selection‘s check boxes?

Question

we are using:

• Delphi 10.3 Rio
• DevExpress QuantumGrid 19.1.2

We have activated in the grid view, the use of "automatic boxes" to select rows/records, within the Indicator area and applying the following configuration:

with AView do
begin
     OptionsSelection.MultiSelect := True,
     DataController.Options:= DataController.Options +[dcoMultiSelectionSyncGroupWithChildren];
     OptionsSelection.MultiSelectMode := msmPersistent;
     OptionsSelection.CheckBoxVisibility := [cbvDataRow, cbvGroupRow, cbvColumnHeader];
     OptionsSelection.CheckBoxPosition := cbpIndicator;
end;

But I can't find an appropriate event that fires every time the user checks or unchecks the box, in order to display the classic legend:

a := AView.DataController.GetSelectedCount;
b := AView.DataController.RecordCount;
Label1.Caption := format('selected = %d of %d' , [a,b]);

Can anyone have an idea how to implement that? Thank you all. A cordial greeting,