     @_lastOnScreenChildIndex = -1
     @_focusedChildIndex = -1
     @_initGestureProps()
+    @_gestureScrollStartPosition = 0
     @_gestureScrollPosition = 0
     @onNextReady =>
       # @jumpToEnd() if @startAtEnd

          begin:      @gestureBegin.bind @
          move:       @gestureMove.bind @
          end:        @gestureEnd.bind @

  mouseWheelEvent: (event) =>
    @_mostRecentMouseWheelEvent = event

  pageDown: -> @animateToValidScrollPosition -@windowSize
  pageUp:   -> @animateToValidScrollPosition @windowSize

  gestureCancel: ->
    @scrollPosition = @_gestureScrollStartPosition

  getMainCoordinate: (pnt) ->
    if @isVertical
      pnt.y
