In the special Picnic levels you can use three types of boosters:

• Shuffle booster mixes the tiles so that new sets available for matching may appear.
•  Bomb booster removes 3 random sets of matching tiles.
•   Undo booster undoes your last move.
• Reverse booster sends from 1 to 3 of your last choosen tiles to a temporary vault. 

How  to use Reverse booster with other boosters:

• When you use Shuffle booster, tiles removed with Reverse booster are also shuffled.
• Bomb booster can remove the tiles which were removed to the  temporary vault.
• You can not use the Undo booster to undo the Reverse booster effect.