This has happened a few times. I have a Samsung Galaxy Appeal, and on at least three occasions, it will randomly start playing the message tone "over the horizon". I cannot make it stop without turning off the phone. I have closed every application running, it is not a message coming in, and it is not a phone call or any other alert. Has anyone else had this happen? The last time this happened, it stopped after three minutes, all on it's own. I had already tried everything and was just looking at it. Any suggestions?