This solution is for design time !
If your Cursor columns are not dynamic then try this:

First make replica table of the cursor in some temporary diractory.
keep table name same as cursor alias name.

open the form in design mode insert a grid control.
select builer for grid.
select free table from temporary directory and populate fields.
select grid for edit go to column where you want to insert check box. an
and insert checkbox.
open Data environment remove temporary table.
open grid properties. remove rowsource.
set rowsource property of grid after creating cursor in yr code.

save form.
delete table from temporary directory.
and run the form.
HTH

Diptesh.