For anyone who has trouble with an app such as I have( mine was the whoisit free app gave me a troubling menu icon in the app switcher that did nothing and wouldn't go away) and even after deleting still has trouble here's what I've done. Wiping the phone, reinstalling the software did not help. It came down to changing permissions to all deny rebooting phone then deleting the app. That's what finally fixed mine. I even got a different phone with same issue cuz I didn't realize it was an app causing the trouble.