     @tag_cell        = @control_row.append('td')
     @tag_title       = @tag_cell.append('h5').text(@_tag_header).attr('class', 'verb_selector_title')
     @tag_selector    = @tag_cell.append('select').attr('name', 'tag_selector')
+    @control_row.append('td') # for extra td
 
 
   constructDataFilter: (options) ->

    @_series_header  = options.series_header or "series_title"
    @_filter_header  = options.filter_header or "filter_title"
    @_tag_header     = options.tag_header or "tag_title"
    @initializeQuestionTable()

    @_page          = 1

      .append('span').attr('class', 'tag')

    tag_spans.text((d) -> d)
    extra = rows.append('td')
    @extra_td_callback(extra)
    @renderCallback(@)

  renderTags: (container, tag_list) ->
