Can any N9 owner say if the double-tap works when: 1. double-tapping display with finger (should work, either way); 2. double-tapping display with non-conductive stylus (if yes, then accelerometer; if no, then touch-screen); 3. double-tapping body outside of display (if yes, then accelerometer; if no, then touch-screen); 4. double-touching the display softly (if no, then accelerometer; if yes, then touch-screen).