app/views/search_across/_group_toggle.html.erb
<% unless @response.documents.blank? %>
<div class="btn-group search-group" role="group" aria-label="Basic example">
<%= link_to 'All results', url_for(search_without_group), class: "btn btn-sm btn-secondary #{'active' unless render_grouped_response?}" %>
<%= link_to 'Grouped by exhibit', url_for(search_with_group), class: "btn btn-sm btn-secondary #{'active' if render_grouped_response?}" %>
</div>
<% end %>