How does it control background processing? I may want to hide a music playing app and let it keep playing, while others may try to close it (and really just hide it) to get the sound to stop, and will fail because it just gets hidden.

Or network file locks, someone uses metro word to open a document and never closes it because the app gets hidden. Even worse, you then take the tablet home and close word, but because your no longer on the network, the server holds the file locked.