At the moment if the N9 is/thinks it its 'horizontal' apps close if you swipe right to left (effectively downwards). Sometimes there is no knowing if the phone thinks it is horizontal, meaning annoyingly you close apps without realising it (especially annoying if you are tracking a run, say).

Is there an app/mod that makes the downward swiping action from top to bottom of the device in portrait the only swipe action that closes an app?

Hope Im making sense!? Im sure people encounter this issue themselves at times?