     @reset_button = @$(@reset_button_sel)
     @undo_button = @$(@undo_button_sel)
     @submit_button = @$(@submit_button_sel)
-    @tracked_elements = @$(@tracked_elements_sel)
+    @tracked_changes = @$(@tracked_changes_sel)
     @tracked_feedback = @$(@tracked_feedback_sel)
     
     @reset_button.click @reset_changes

class @TrackChanges
  reset_button_sel: '.reset-changes'
  undo_button_sel: '.undo-change'
  tracked_elements_sel: 'span.del, span.ins'
  tracked_feedback_sel: '.feedback-area.track-changes'
  submit_button_sel: '.submit-button'
  tracker: null

  undo_change: (event) =>
    event.preventDefault()
    keyOfLatestChange = 0
    @tracked_changes = @$(@tracked_changes_sel)
    @tracked_changes.each ->
      key = parseInt($(@).attr('data-cid'))
      if key > keyOfLatestChange
        keyOfLatestChange = key
    @tracker.rejectChange('[data-cid="'+ keyOfLatestChange + '"]')
