this has happened a million times when using the stamp tool in photoshop: i am happily stamping away, when suddenly i hear a noise by the system after which i can not use the keyboard any longer. the noise sounds like a key turning in a lock and most keys get locked indeed (arrow keys are still functioning) in all applications including the finder. sometimes i manage to somehow unlock them again by keep stamping, other times i dont and have to restart (!) the machine to unlock the keyboard. how can i get rid of this annoyance or what is the trick to unlock the keyboard again?