Probe lets you move back and forth through the move sequence, to explore game variations.
Reverses the last pair of moves in the game: Probe's and yours. You can undo moves all the way back to the beginning of the game, even if you save the game and later resume it.
Replays the next pair of moves you previously undid, provided you didn't undo several moves and then make a new one.
Begins a new game from the original position.