The Snapshot buttons in the toolbar.
In some solitaires you will reach “decision points” where you are not sure what the best move might be. Snapshots allow you to remember these decision points and easily return to them later. If the move you originally made doesn’t work out well, you can return to the snapshot position and try a different move instead.
Click the Undo to Snapshot button to undo moves until the most recent snapshot is reached. If there are no prior snapshots, it will undo all the way back to the start of the game.
Click the Redo to Snapshot button to redo moves until the next snapshot is reached. If there are no more snapshots, it will redo all the rest of your moves.
You can take as many snapshots in a game as you like. To delete a snapshot, return to the snapshot position and then click the Snapshot button again.