anchor.diff:        <% elsif @content.is_a? Content::Resource %>
           <%= link_to t('content.actions.revise'), annotate_resource_path(@casebook, @resource), class: 'action edit one-line' %>
         <% end %>
  -    <% elsif action_name == 'show' ## preview mode %>
  +    <!-- preview mode -->
  +    <% elsif action_name == 'show' %>
         <% if @content.is_a? Content::Casebook %>
           <%= button_to t('content.actions.publish'), casebook_path(@casebook), method: :patch, params: {content_casebook: {public: true}}, class: 'action publish one-line' %>
           <%= link_to t('content.actions.revise'), layout_casebook_path(@casebook), class: 'action edit one-line' %>
  
positive.code:   <% end %>
  <% else %>
    <% if @casebook.owners.include?(current_user) %>
      <% if @casebook.public ## published version %>
        <% if @content.is_a? Content::Casebook %>
          <%= link_to t('content.actions.revise'), edit_casebook_path(@casebook), class: 'action edit one-line' %>
        <% elsif @content.is_a? Content::Section %>
  
negative.code: <!-- draft mode -->
  <% if action_name.in? %w{edit layout annotate} %>
    <% if @content.is_a? Content::Casebook %>
      <%= button_to t('content.actions.publish'), casebook_path(@casebook), method: :patch, params: {content_casebook: {public: true}}, class: 'action publish one-line' %>
  