iTunes 11 continued to play after quitting

I just experienced a head-scratcher. While playing a tune in iTunes 11 on 10.8.2, I experienced the annoying disappearing cursor. I have determined that the cursor disappears for iTunes only (reappearing if I switch to something else) after I have used the visualizer. I have not determined if it is specific to only one visualizer or if it happens with others because, frankly, I use G-Force and cannot bring myself to even look at another visualizer. That was not the strangeness though. The only remedy for the cursor is to quit iTunes and restart but this time, after quitting, the music continued to play. ITunes was definately not running yet I was still Airplaying to me Airport Express and everything. When I relaunched iTunes and hit play, a second tune played right over the other one at the same time. Only when the first song ended, did it stop. Very odd indeed.