       Math.abs $(sourceNode).offset().top - $(targetNode).offset().top
 
     verticalBranch: (node, lastChild) ->
-      this.betweenTop(node, lastChild) + this.middleHeight(lastChild)
+      @betweenTop(node, lastChild) + @middleHeight(lastChild)
 
   branchProp =
     base:

      "margin-left: 2em; " +
      "height: #{height}px; " +
      "z-index: -1; " +
      this.base

    horizontal: (marginTop) ->
      "margin-top: -#{marginTop}px; " +
      "margin-left: -2em; " +
      "width: 2em; " +
      "z-index: -2; " +
      this.base

  pseudoElement =
    addHorizontal: (node) ->

      allParents  = $(node).prevAll('.panel-parent')
      parentIds   = $.map(allParents, (el) -> $(el).attr 'id')
      actualIds   = similarItems(nodeClasses, parentIds)

      # add current node id
      actualIds.push $(node).attr('id')
      # get array of jquery elements from actual ids
      actualCollection = getElements(actualIds)
      # update vertical pseudoelement of actual elements
      that = this
      $.each(actualCollection, (i, element) ->
        that.uptVertical(element)
      )

  findPanelHeader = (object) ->
    object.find('.panel').find('.panel-header')
