method edit_selected () =
match self#selected_rr with
None -> ()
| Some rr ->
let row = rr#iter in
let item = store#get ~row ~column: col_data in
let params = self#params_for_item item in
match C.simple_get ~width: 500 "Edit item" params with
C.Return_ok -> self#display_item row item
| _ -> ()