method private _cb__view_to_selection_changed = fun () ->
match select_w#view2.SW.st_view#selection#get_selected_rows with
| [path] ->
let iter = select_w#store2#get_iter path in
let (_, cmodel) = select_w#store2#get_data ~row:iter in
self#_set_constr_model cmodel;
glade#add_constr_button#misc#set_sensitive true
| _ ->
self#_set_constr_model empty_constr_store;
glade#add_constr_button#misc#set_sensitive false