       registration_data_series = (registration, index) ->
         # The registration image select button colors.
         COLORS = ['LightGreen', 'LightYellow', 'LightCyan', 'LemonChiffon']
-      
+    
         key = registration.title
-      
+    
         # TODO - Wrap the key in a registration parameters pop-up hyperlink.
         # Return the data series format object.
         key: key

      yFormat: yFormat
      highlightBolusArrival: (chart) ->
        highlightBolusArrival(session, chart)

    # Formats the intensity selection block for the given session.
    # Padding is added to each button sufficient to center the
    # button under the intensity chart x-axis tick marks.
    #
    # @param element the selection Angular jQueryLite element
    formatSelection: (element) ->
      formatRow = (row) ->
        # The width of the entire row.
        rowWidth = row[0].clientWidth
        # The selection key label and buttons.
        children = row.children()
        # The width of the first key element holding the label,
        # e.g. 'Scan'.
        keyWidth = children[0].clientWidth
        # The button width without padding.
        buttonWidth = children[1].clientWidth
        # The number of buttons.
        buttonCnt = children.length - 1
        # The width available to pad the buttons.
        available = rowWidth - keyWidth - (buttonCnt * buttonWidth) 
        # The button left and right pad amount. Since the left-most
        # and right-most buttons are only padded on one side, count
        # those two buttons as one for the purpose of computing the
        # pad amount.
        pad = available / (2 * (buttonCnt - 1))
        # The buttons include all but the first child.
        buttons = (ng.element(children[i]) for i in [1..buttonCnt])
        
        
        # FIXME - this has no effect. Perhaps the margin precision
        # is too large, since setting it to a precision > 3 in the
        # style sheet fails. But setting margin here to an int
        # has no effect either.
        #
        # TODO - remove the css margin and get this to work.
        #
        # # Add a right pad for all but the last button.
        # for btn in buttons[0...buttonCnt-1]
        #   btn.css('margin-right', pad)
        # # Add a left pad for all but the first button.
        # for btn in buttons[1...buttonCnt]
        #   btn.css('margin-left', pad)
      
      # Format each row.
      for childDom in element.children()
        child = ng.element(childDom)
        if child.hasClass('row')
          formatRow(child)
        else
          this.formatSelection(child)
  ]

    highlightBolusArrival = (session, chart) ->
      # If the bolus arrival index is zero, then it does not have
      # have a tick mark, so bail.
      if not session.bolusArrivalIndex
        return
      # Select the SVG element.
      svg = d3.select(chart.container)
