anchor.diff:  
         onTouchStart: (ev) => 
           ev.preventDefault()
  -        @onClick(ev)
  -        hist.dragging = true
           @local.touched = true
           save hist
           save @local
  +        @onClick(ev)
   
         onTouchMove: (ev) => ev.preventDefault(); @onMouseMove(ev)
         onTouchEnd: (ev) => ev.preventDefault(); @onMouseUp(ev)
  
positive.code: #   * If a region is selected, clicking anywhere except within the 
  #     decision board will deselect the region.
  #
  ##
  # Selected region background
  #   * A selection region background follows the mouse in the histogram if:
  
negative.code:     # whether to show the shaded opinion selection region in the histogram
      draw_selection_area = !hist.selected_opinion && 
                              @root.proposal_mode == 'results' &&
                              (hist.selected_opinions || 
                                (!@local.touched && @local.mouse_opinion_value && !@local.hoving_over_avatar)) 
  
      DIV 
        className: 'histogram'
  