In Open Yahtzee 1.7 and probably also in earlier versions a bug exists that allows the user to do an "undo" before the first move of a new game and by doing so grants the option of keeping dices from the last game in the first move.
Steps to reproduce:
1. Start a new game roll the dice 3 times and score some where.
2. Game->New Game
4. Tick the 'keep' check box and re-roll.
By doing the mentioned steps the user is actually given 6 rolls on the first move of the game instead of just 3.