columngrid and checkbox

I have a problem with advcolumngrid using a checkbox in the grid.

The issue is similar to what I had before with the combobox, which is solved by some code I had to add (Thnx Bruno!!)

I set the checkbox in the grid this way :
AGvhf.CheckCell(1,v);

However it does not show, neither the ones that are not checked.

How can I solve this?

Best regards,

Ruud