I've started using firefox but unfortunately when I use it in tablet mode with type cover removed or folded back I can't get the onscreen keyboard to appear at all. Weirdly there's no keyboard icon available in the task bar to manually bring it up either. When I re-snap the type cover on the on-screen keyboard icon DOES appear in the taskbar!! The on-screen keyboard is popping up in Edge in tablet mode. Surface pro 3, Win 10, Firefox 42.0, Surface pro 4 type cover... Help!