Index: app/controllers/issues_controller.rb
===================================================================
--- app/controllers/issues_controller.rb	(revision 3604)
+++ app/controllers/issues_controller.rb	(working copy)
@@ -224,7 +224,7 @@
       text = @issue.description
     end
     content = "#{ll(Setting.default_language, :text_user_wrote, user)}\\n> "
-    content << text.to_s.strip.gsub(%r{<pre>((.|\s)*?)</pre>}m, '[...]').gsub('"', '\"').gsub(/(\r?\n|\r\n?)/, "\\n> ") + "\\n\\n"
+    content << text.to_s.strip.gsub(%r{<pre>((.|\s)*?)</pre>}m, '[...]').gsub('\\', '\\\\\\\\').gsub('"', '\"').gsub(/(\r?\n|\r\n?)/, "\\n> ") + "\\n\\n"
     render(:update) { |page|
       page.<< "$('notes').value = \"#{content}\";"
       page.show 'update'