method private _cb__after_down = fun row_down row_up ->
let (table_up, model_up) = select_w#store2#get_data ~row:row_up#iter
and (table_down, model_down) = select_w#store2#get_data ~row:row_down#iter in
model_up#move_constraints_to table_down.SQL_db.ta_name model_down