Given constraints and preferences, the system will try to solve the problem using constraint satisfaction problem solving techniques(eg. backtracking and constraint propagation). But the problem is that the inputs are static. Therefore the problem solving should be redone from the scratch when inputs are changed. Furthermore, the system tightly integrates problem solving methods(constraint propagation, backtracking, consistency check) with decision making, by which the user lose the control of solutions. For these reasons, the system is not so much useful for incremental revision support under dynamic constraints and preferences