The funniest thing is that the quote they are suing over is not even a direct quote. Faulkner wrote "The past is never dead. It's not even past." -- that's different from what is in the movie, which is "The past is not dead! Actually, it’s not even past."
This is not a lawsuit to be tossed aside lightly. It should be thrown with great force. Oops! I hope Dorothy Parker's literary estate is not going to sue me for that.