I was just going to mention that myself. As far as I can tell, no developer has picked up on it. I think it would run any app, whereas, the Samsung multi-window may be limited to a smaller set of apps but I don't know for sure and I hope I am wrong here. Also, as another option, there is the app called "stickit!" which also creates a window to view media as well as youtube. This window can be resized as well as put in background so you can listen to music and do some other "task".