Hide checkboxes on children


I have a treeGrid with folders wich have children items. The first column permit to check or uncheck folders and items.

I would like to display checkboxes for folders and hide them for children.
something like that but the checkboxes column on left side :

If someone has an idea ?


In xml you can have for ones where you need not checkboxes. type=ro will change cell type to readonly, so it will render self as plain text