fixes #2422

app/models/post.rb

@@ -838,11 +838,20 @@ class Post < ActiveRecord::Base
       favorited_user_ids.map {|id| User.find(id)}
     end
 
-    def favorite_groups
+    def favorite_groups(active_id=nil)
       @favorite_groups ||= begin
-        CurrentUser.user.favorite_groups.select do |favgroup|
+        groups = []
+
+        if active_id.present?
+          active_group = FavoriteGroup.where(:id => active_id.to_i).first
+          groups << active_group if active_group && active_group.contains?(self.id)
+        end
+
+        groups += CurrentUser.user.favorite_groups.select do |favgroup|
           favgroup.contains?(self.id)
         end
+
+        groups.uniq
       end
     end
   end

app/presenters/post_presenter.rb

@@ -205,7 +205,7 @@ class PostPresenter < Presenter
   end
 
   def has_nav_links?(template)
-    (CurrentUser.user.enable_sequential_post_navigation && template.params[:tags].present? && template.params[:tags] !~ /(?:^|\s)(?:order|ordfav|ordpool):/) || @post.pools.any? || @post.favorite_groups.any?
+    (CurrentUser.user.enable_sequential_post_navigation && template.params[:tags].present? && template.params[:tags] !~ /(?:^|\s)(?:order|ordfav|ordpool):/) || @post.pools.any? || @post.favorite_groups(active_id=template.params[:favgroup_id]).any?
   end
 
   def post_footer_for_pool_html(template)

app/views/posts/partials/show/_favorite_groups.html.erb

@@ -1,6 +1,6 @@
 <div id="favgroup-nav">
   <ul>
-    <% post.favorite_groups.each do |favgroup| %>
+    <% post.favorite_groups(active_id=params[:favgroup_id]).each do |favgroup| %>
       <li>
         <% klass = "active" if favgroup.id == params[:favgroup_id].to_i %>
 

app/views/posts/partials/show/_nav_links.html.erb

@@ -8,7 +8,7 @@
       <%= render "posts/partials/show/pools", :post => post %>
     <% end %>
 
-    <% if post.favorite_groups.any? %>
+    <% if post.favorite_groups(active_id=params[:favgroup_id]).any? %>
       <%= render "posts/partials/show/favorite_groups", :post => post %>
     <% end %>
   </div>