anchor.diff:      m_x = ev.pageX
       @local.opinion_center = 2 * (m_x - h_x) / h_w - 1
       @local.mousing_over_histogram = Math.abs(@local.opinion_center) <= 1
  +
  +    if @local.mousing_over_histogram
  +      hist = fetch 'histogram'
  +      opinions_in_focus = @getOpinionsInCurrentFocus(ev)
  +      @local.click_will_defocus = JSON.stringify(hist.selected_opinions) == JSON.stringify(opinions_in_focus)
       save @local
   
     render : ->
  
positive.code:       # We'll show opinions within +/- filter_width of opinion_center.
        selected_opinions = (o.key for o in all_opinions when o.stance < opinion_center + @filter_width && o.stance > opinion_center - @filter_width)
  
      # Deselect if we've reclicked on same selection
      if JSON.stringify(hist.selected_opinions) == JSON.stringify(selected_opinions) || selected_opinions.length == 0
        hist.selected_opinions = null
      else
        hist.selected_opinions = selected_opinions
      save hist
  
    movingThroughHistogram : (ev) -> 
      # We can calculate the opinion_center (the slider value about which we will select opinions)
  
negative.code:               whiteSpace: 'nowrap'
                marginTop: -18
  
              if @local.click_will_defocus then 'Click to defocus' else 'Click to focus'
  
        DIV style: {height: segment_selection_margin}
  
  