SMART datagrid v.1 > Classes > ColumnHeader
The location of check mark being displayed in column header. 
It is specified by HeaderItemLocation constant.
Defaults to HeaderItemLocation.NONE.
    column.setHeader({
        checkLocation: DataLudi.HeaderItemLocation.RIGHT
    });
    // or can set individually.
    column.header().setCheckLocation(DataLudi.HeaderItemLocation.RIGHT);