I uninstalled/installed FF. The opening/running in the background stopped. Downloaded the update FF opens & runs in the background again! You can't choose to disable cookies. AdBlock Plus, Privacy Settings, WebRTC & CanvasBlocker are no longer supported. If you quit/force close the browser & disble it from running in the background it will still do so. I shouldn't have to keep uninstalling/installing FF to make it behave properly. The dev team must fix this issue asap.