This is a problem with Jelly bean really but thought I'd try here for a solution. When I was trying to download a picture from the chrome browser, for whatever reason it didn't work. Now for some reason I have this endless download in my notification bar. I can't swipe it away and it doesn't appear to be actually downloading anything, it's just the animation with no timer or name. Turning off the nexus 7 does nothing and turning off the wifi still leaves the annoying animation. Is there anything I can do short of resetting the device?