Sudoku Players' Forum (clone)

I play a Google Play Futoshiki. It allow me to set up possible values but when I come to having to make a guess and derive the effect of that I have to delete many my possibles and it might go a long way before discovering that the guess was wrong then I have to do tons of work to sort it. I just dont want to continue and so easy to make a mistake anyway. Sane for Sudoku- once you set up possibles you only want to only eliminate once you are sure. A app should allow you to say a possibles color to remind that is a guess, another for an result of guess, another for elimination from the guess. What apps have scenario tools do that? Sudoku.com doesnt for sure.