How is one supposed to pass this level when no keys drop? There is opportunity to drop, but they just don't . The last time I played it dropped on the last move when it had plenty of opportunities during gameplay...NOT cool.
Take your pick, column 2 or 8 then stick to it. 1st priority is to get the popcorn. Stripes for column 3 or 7 can help an lot. The more candies you can drop through those columns will release the key sooner. They are up there in the queue.
Collect the keys using stripes or color bombs to unlock the third ingredient and at the same time work on growing the popcorns to release the other two ingredients.
