code: function _pointMouseMove(e) {
          var self = e.target,
              bezierEditor = self.bezierEditor,
              curveBoundingBox = bezierEditor._getCurveBoundingBox(),
              left = curveBoundingBox.left,
              top  = curveBoundingBox.top,
              x = e.pageX - left,
              y = e.pageY - top - HEIGHT_ABOVE;
  
          updateTimeProgression(bezierEditor.curve, x, y);
  
          if (e.pageX === 0 && e.pageY === 0) {
              return;
          }
  
          handlePointMove(e, x, y);
      }
docs: Handle mouse move in <button> element
  
  @param {Event} e Mouse move event