Requires some margin to trigger

[X-Ryl669]

If you use a touchpad, it's very hard not to swipe vertically by a little bit while swiping horizontally. Thus, I think this line:

        if (Math.abs(deltaX) > 0 && Math.abs(deltaY) == 0)

should read instead:

        if (Math.abs(deltaX) > horzThreshold && Math.abs(deltaY) < vertThreshold)

or, just take the ratio (if you swipe more on horizontal axis than vertical axis):

        var horzScale = 1e6;
        if (Math.abs(deltaX) / Math.abs(deltaY) > horzScale)
// This works even if deltaY is zero, since +Inf > any number

[totu]

@X-Ryl669 Would you like to make a pull request with the change?