I've been having a really weird problem with my iPad (3, iOS 7) since yesterday. Most of the time I keep the sound completely off. Yesterday I turned it on briefly to test out the Facetime app for the first time, and then turned it down to mute again. But even though the sound is supposedly on mute (and I have checked this several times using the sound control button to turn the volume up a bit and then back down to mute), I am now hearing certain sounds: the new mail notification ping, the keyboard typing sounds, the "click" when I turn the iPad off. In-app music and sound effects, on the other hand, are still muted. I've tried restarting the iPad (both on the spot and after shutting it down cold for about ten minutes) and the same thing's still happening. I've never had an issue with the mute not muting *all* the sounds before, so I find this inexplicable. Does anyone know what might have caused this and/or how to get the mute function working properly again?