There is a problem in the tactics trainer that allows several solutions and gives a correct solution as wrong.
http://www.chess.com/tactics/?id=25974
FEN: r2q2k1/8/2p2rp1/1pPp1p2/p2Q1P2/P7/1P2PK2/6RR w - - 0 1
After 1.Rxg6+ Kf7, then Stockfish 5 gives 2. Rgh6 as an equally correct move, in addition to 2. Rxf6+ as demanded by the trainer.
There is a problem in the tactics trainer that allows several solutions and gives a correct solution as wrong.
http://www.chess.com/tactics/?id=25974
FEN: r2q2k1/8/2p2rp1/1pPp1p2/p2Q1P2/P7/1P2PK2/6RR w - - 0 1
After 1.Rxg6+ Kf7, then Stockfish 5 gives 2. Rgh6 as an equally correct move, in addition to 2. Rxf6+ as demanded by the trainer.