On the probe demo, when I add "mouseWheel: true" to support mousewheel on desktop i can't get instant update of Y position. It updates when i stop scrolling, but does not update instantly. I assume i need an event that triggers when the mousewheel starts scrolling. The same issue is with the trackpad on my macbook.
myScroll = new iScroll('#wrapper', { mouseWheel: true, probeType: 3 });
myScroll.on('scroll', updatePosition);
myScroll.on('scrollEnd', updatePosition);
myScroll.on('mousewheel', updatePosition); // does not seem to work, help pls :D