Sorry, I must be wrong in my expressions, it is actually the selection of a row in a grid and not a pointer.
Because the source of the grid is a cursor, I have to make a new SELECT whenever I want to make a change of a record. It is not normal to try to change a cursor via grid, but it is the way the people work here, and I am new on this project, so I cannot use a view, which would be the more logic (and easier?) way.