anchor.diff:  <%-
     @body_classes ||= []
  -  keyboard_navigation = yield :keyboard_navigation
  +  keyboard_navigation = (yield :keyboard_navigation).presence
     left_side = nil
     left_side_custom = nil
  -  right_side = yield :right_side
  -  wizard = yield :wizard_box
  -  top_nav = yield :top_nav
  +  right_side = (yield :right_side).presence
  +  wizard = (yield :wizard_box).presence
  +  top_nav = (yield :top_nav).presence
   
     content_for :pre_html do
       @body_class_no_headers = @headers == false
  
positive.code:     <a id="header-logo" href="<%= root_url %>"><%= t 'links.dashboard', "My Dashboard" %></a>
      <b id="header-logo-secondary"></b>
      <div id="topbar">
        <% if (identity = yield :identity) %>
          <%= identity %>
        <% else %>
          <%- cache_if(!@real_current_user, [@current_user || 'nobody', 'identity-15m'], :expires_in => 15.minutes) do -%>
  
negative.code:     @show_fixed_bottom = (@fixed_warnings.present? || (@real_current_user && @real_current_user != @current_user)) && (!@body_class_no_headers || @outer_frame)
      @body_classes << "no-headers" if @body_class_no_headers
      unless (@body_classes.include? "no-headers") || (@show_left_side == false)
        left_side = (yield :left_side).presence
        left_side_custom = (yield :left_side_custom).presence
        @show_left_side ||= (section_tabs.length > 0 || left_side_custom.try(:length))
      end
      @body_classes << "with-left-side" if @show_left_side
  