diff --git a/app/views/memos/edit.html.erb b/app/views/memos/edit.html.erb
index 35543398f..04d95ae86 100644
--- a/app/views/memos/edit.html.erb
+++ b/app/views/memos/edit.html.erb
@@ -1,5 +1,5 @@
 <!-- <h1>New memo</h1> -->
-<% @replying ||= false %>
+<% @replying = !@memo.parent.nil? %>
 <h3><%=l(:label_memo_edit)%></h3>
 <%= labelled_form_for(@memo, :url => forum_memo_path(@memo.forum_id, @memo)) do |f|  %>
   <% if @memo.errors.any? %>
@@ -13,7 +13,7 @@
     </div>
   <% end %>
   <div class="actions">
-    <p><%= f.text_field :subject, :required => true, :size => 96 %></p>
+    <p><%= f.text_field :subject, :required => true, :size => 96 ,:readonly => @replying%></p>
     <p>
       <% unless @replying %>
         <% if @memo.safe_attribute? 'sticky' %>