diff --git a/app/helpers/post_versions_helper.rb b/app/helpers/post_versions_helper.rb
index cf2e0d9c8..aa9716d58 100644
--- a/app/helpers/post_versions_helper.rb
+++ b/app/helpers/post_versions_helper.rb
@@ -3,16 +3,12 @@ module PostVersionsHelper
     diff = post_version.diff(post_version.previous)
     html = []
     diff[:added_tags].each do |tag|
-      html << '<ins>+' + link_to(tag, posts_path(:tags => tag)) + '</ins>'
-    end
-    diff[:obsolete_added_tags].each do |tag|
-      html << '+<ins class="obsolete">' + link_to(tag, posts_path(:tags => tag)) + '</ins>'
+      prefix = diff[:obsolete_added_tags].include?(tag) ? '+<ins class="obsolete">' : '<ins>+'
+      html << prefix + link_to(tag, posts_path(:tags => tag)) + '</ins>'
     end
     diff[:removed_tags].each do |tag|
-      html << '<del>-' + link_to(tag, posts_path(:tags => tag)) + '</del>'
-    end
-    diff[:obsolete_removed_tags].each do |tag|
-      html << '-<del class="obsolete">' + link_to(tag, posts_path(:tags => tag)) + '</del>'
+      prefix = diff[:obsolete_removed_tags].include?(tag) ? '-<del class="obsolete">' : '<del>-'
+      html << prefix + link_to(tag, posts_path(:tags => tag)) + '</del>'
     end
     diff[:unchanged_tags].each do |tag|
       html << '<span>' + link_to(tag, posts_path(:tags => tag)) + '</span>'
diff --git a/app/models/post_version.rb b/app/models/post_version.rb
index 0893aa282..95e65d204 100644
--- a/app/models/post_version.rb
+++ b/app/models/post_version.rb
@@ -93,8 +93,8 @@ class PostVersion < ActiveRecord::Base
     removed_tags = old_tags - new_tags
 
     return {
-      :added_tags => added_tags & latest_tags,
-      :removed_tags => removed_tags - latest_tags,
+      :added_tags => added_tags,
+      :removed_tags => removed_tags,
       :obsolete_added_tags => added_tags - latest_tags,
       :obsolete_removed_tags => removed_tags & latest_tags,
       :unchanged_tags => new_tags & old_tags,