           @scrollRatio
           @childrenOffset
           @childrenSize
+          childrenOffsetDelta
           windowSize
           focusedChild
           firstOnScreenChildIndex

    firstOnScreenChildIndex = -1 if firstOnScreenChildIndex == children.length

    if (
        childrenOffsetChanged ||
        firstOnScreenChildIndex != @_firstOnScreenChildIndex ||
        lastOnScreenChildIndex  != @_lastOnScreenChildIndex ||
        focusedChildIndex       != @_focusedChildIndex ||

    else
      @_spMinusTp = _scrollPosition - @trackingPositionFromPendingGeometry

    @_updateOnScreenInfo @_childrenOffset - oldChildrenOffset

  _updateOnScreenInfo: (childrenOffsetDelta)->
    {isVertical, windowSize} = @

    focusedChild = @_pendingState._focusedChild
