EventX = 0 Fix

Found a little bug that when dragging the slider on a desktop.

When dragging the slider and the mouse goes outside the view of the browser `eventX` then goes into the negative, which is fine. But there is a split second where `eventX` equals `0` which then causes line 826 to be false and reverts to the touch events, which doesn't exists and throws an error trying to find `[0]` of  `event.touches`.