 
           ####
           # implement option (2) above
-          @setState { users_to_highlight_in_histogram : [] }
+          @setState { users_to_highlight_in_histogram : null }
 
   setStickyHeader : ->
     # Sticky decision board. It is here because the calculation of offset top would 

      opinions : []

  getInitialState : ->
    users_to_highlight_in_histogram : []
    selected_segment_in_histogram : [null, null]

  # TODO: add prop types here

                for bar in bars
                  R.td className:"histogram_bar", style: {width: avatar_size},
                    for opinion in bar
                      Avatar key:"#{opinion.user_id}", user: opinion.user_id, 'data-segment':segment, style:{height: avatar_size, width: avatar_size, opacity: if @props.users_to_highlight_in_histogram && !_.contains(@props.users_to_highlight_in_histogram, opinion.user_id) then '.2' else '1.0'}

##
# Slider
