     @afterRender()
 
   beforeRender: ->
-    @_hide_columns_below_n(@_n_threshold)
+    @_hide_columns_below_n(@_n_threshold) unless @_show_unstable_data
+
+  show_unstable_data: (b) ->
+    @_show_unstable_data = b
+    @filter_data(@_filters)
+    @render()
 
   _render: -> null
   afterRender: ->
+    @renderUnstableLegend()
     @_adjust_svg_dimensions()
 
   _adjust_svg_dimensions: ->

      .attr('transform', "translate(10, 3)")
      .attr('alignment-baseline', 'middle')

  # FIXME
  renderFilterLegend: =>
    @_checked or= {}

      @data(@raw_data)

  _hide_columns_below_n: (n) ->
    columns_are_hidden = false
    n_value = @series_2_label_sum
    select_columns_above = (n, data) ->
      values = data.values.filter((v) -> n_value(v) >= n)
      columns_are_hidden = true if values.length < data.values.length
      { key: data.key, values: values }
    @_data = (d for d in (select_columns_above(n, d) for d in @_data) when d.values.length > 0)
    @_columns_are_hidden = columns_are_hidden
    @_show_unstable_legend = @_show_unstable_legend or columns_are_hidden # set once

  # pre-establishes indexes for the spacing and grouping of series 1 data
  # based on its contents (necessary because of the variable length of data within
