diff -u thunderbird-14.0~b3+build1/debian/changelog thunderbird-14.0~b3+build1/debian/changelog
--- thunderbird-14.0~b3+build1/debian/changelog
+++ thunderbird-14.0~b3+build1/debian/changelog
@@ -1,3 +1,9 @@
+thunderbird (14.0~b3+build1-0ubuntu3) quantal; urgency=low
+
+  * messaging-menu: ignore case when comparing email addresses
+
+ -- Thomas Jaeger <ThJaeger@gmail.com>  Wed, 27 Jun 2012 19:14:29 -0400
+
 thunderbird (14.0~b3+build1-0ubuntu2) quantal; urgency=low
 
   * Add missing file
diff -u thunderbird-14.0~b3+build1/debian/messagingmenu/modules/MessagingMenu.jsm thunderbird-14.0~b3+build1/debian/messagingmenu/modules/MessagingMenu.jsm
--- thunderbird-14.0~b3+build1/debian/messagingmenu/modules/MessagingMenu.jsm
+++ thunderbird-14.0~b3+build1/debian/messagingmenu/modules/MessagingMenu.jsm
@@ -463,18 +463,18 @@
       let sender = aHeaders.get("sender").replace(re, "$1");
       let from = aItemHeader.author.replace(re, "$1");
 
-      return sender != from;
+      return sender.toLowerCase() != from.toLowerCase();
     }, "Possible automated message (Sender != From)");
 
     state.requestAttentionIfTrue(function() {
       let recipients = aItemHeader.recipients.split(",");
       let re = /.*<([^>]*)>/; // Convert "Foo <bar>" in to "bar"
       for (let i in recipients) {
-        let recipient = recipients[i].replace(re, "$1");
+        let recipient = recipients[i].replace(re, "$1").toLowerCase();
 
         for (let id in fixIterator(MailServices.accounts.allIdentities,
                                    Ci.nsIMsgIdentity)) {
-          if (recipient.indexOf(id.email) != -1)
+          if (recipient.indexOf(id.email.toLowerCase()) != -1)
             return true;
         }
       }