A Japanese district court ruled that S. Korea's Samsung infringed an Apple (AAPL) patent on a "bounce-back" feature. Samsung doesn't use the feature, which returns a user to the beginning of a document on a smartphone or tablet, on its newer devices. Although the Tokyo judge found for Apple, he didn't immediately specify damages. The U.S. Patent and Trademark office in April ruled Apple's patent invalid, allowing older Samsung phones with the feature to remain on sale. Apple shares fell 0.8% to 413.50.