I was listening to one song near it's ending and as it was transitioning to another song, I clicked on the time slide and it ended up playing two songs at once! Try it out. Right when one song is ending at your transition time (default is 5 seconds I think), right before it moves on to the next song, click anywhere on the time slide and it should be playing the next song at the beginning and the last song at the place where you clicked on the slide. If you click too early, you'll just jump back to that place on your current song and won't move on to the next. Too late and it'll just play the next song by itself at the part you clicked at.