diff --git a/mailnews/base/public/nsIMsgIdentity.idl b/mailnews/base/public/nsIMsgIdentity.idl
index 7f2200da606..f2d64df4b48 100644
--- a/mailnews/base/public/nsIMsgIdentity.idl
+++ b/mailnews/base/public/nsIMsgIdentity.idl
@@ -49,7 +49,7 @@
  */
 
 
-[scriptable, uuid(D3B4A420-D5AC-11d2-806A-006008128C4E)]
+[scriptable, uuid(2b165a14-1ac1-4c32-8cc5-72e2937d5be9)]
 interface nsIMsgIdentity : nsISupports {
   /* internal preferences ID */
   attribute string key;
@@ -121,6 +121,11 @@ interface nsIMsgIdentity : nsISupports {
   attribute boolean showSaveMsgDlg;
   attribute string directoryServer;
   attribute boolean overrideGlobalPref;
+  /**
+   * If this is false, don't append the user's domain
+   * to an autocomplete address with no matches
+   */
+   attribute boolean autocompleteToMyDomain;
   /**
    * valid determines if the UI should use this identity
    * and the wizard uses this to determine whether or not
diff --git a/mailnews/base/util/nsMsgIdentity.cpp b/mailnews/base/util/nsMsgIdentity.cpp
index 05ea8d47026..fcf21a66454 100644
--- a/mailnews/base/util/nsMsgIdentity.cpp
+++ b/mailnews/base/util/nsMsgIdentity.cpp
@@ -573,6 +573,7 @@ NS_IMPL_FOLDERPREF_STR (StationeryFolder, "stationery_folder")
 NS_IMPL_IDPREF_BOOL(ShowSaveMsgDlg, "showSaveMsgDlg")
 NS_IMPL_IDPREF_STR (DirectoryServer, "directoryServer")
 NS_IMPL_IDPREF_BOOL(OverrideGlobalPref, "overrideGlobal_Pref")
+NS_IMPL_IDPREF_BOOL(AutocompleteToMyDomain, "autocompleteToMyDomain");
 
 NS_IMPL_IDPREF_BOOL(Valid, "valid")
 
diff --git a/mailnews/mailnews.js b/mailnews/mailnews.js
index c7e5412682c..7a6b5d215b9 100644
--- a/mailnews/mailnews.js
+++ b/mailnews/mailnews.js
@@ -326,7 +326,7 @@ pref("mail.identity.default.compose_html", true);
 pref("mail.identity.default.valid", true);
 pref("mail.identity.default.fcc",true);
 pref("mail.identity.default.fcc_folder","mailbox://nobody@Local%20Folders/Sent");
-
+pref("mail.identity.default.autocompleteToMyDomain", false);
 
 // keep these defaults for backwards compatibility and migration
 
@@ -424,6 +424,8 @@ pref("mail.server.default.manualMarkMode",0); // 0 == "move to junk folder", 1 =
 // by changing this pref. Typical values are .99, .95, .90, .5, etc. 
 pref("mail.adaptivefilters.junk_threshold", 90); 
 
+pref("mail.autoComplete.highlightNonMatches", true);
+
 // if true, we'll use the password from an incoming server with
 // matching username and domain
 pref("mail.smtp.useMatchingDomainServer", false);
diff --git a/xpfe/components/autocomplete/resources/content/autocomplete.xml b/xpfe/components/autocomplete/resources/content/autocomplete.xml
index acbbdd69487..4f68bed1c8c 100644
--- a/xpfe/components/autocomplete/resources/content/autocomplete.xml
+++ b/xpfe/components/autocomplete/resources/content/autocomplete.xml
@@ -136,7 +136,13 @@
       <property name="autoFillAfterMatch"
                 onset="this.setAttribute('autoFillAfterMatch', val); return val;"
                 onget="return this.getAttribute('autoFillAfterMatch') == 'true';"/>
-                
+
+      <!--  if this attribute is set, allow different style for 
+            non auto-completed lines -->
+      <property name="highlightNonMatches"
+                onset="this.setAttribute('highlightNonMatches', val); return val;"
+                onget="return this.getAttribute('highlightNonMatches') == 'true';"/>
+
       <!-- toggles a second column in the results list which contains
            the string in the comment field of each autocomplete result -->
       <property name="showCommentColumn"
@@ -528,6 +534,7 @@
           this.mFailureCount = 0;
           this.mFailureItems = 0;
           this.mDefaultMatchFilled = false; // clear out our prefill state.
+          this.removeAttribute("noMatchesFound");
 
           // tell each session to start searching...
           for (var name in this.mSessions)
@@ -664,6 +671,9 @@
           else
             this.removeAttribute("nomatch");
           
+          if (!this.mDefaultMatchFilled && this.highlightNonMatches)
+            this.setAttribute("noMatchesFound", true);
+          
           // if we have processed all of our searches, and none of them gave us a default index,
           // then we should try to auto fill the input field with the first match. 
           // note: autoFillInput is smart enough to kick out if we've already prefilled something...
@@ -731,6 +741,7 @@
           }
           
           this.mNeedToComplete = false;
+          this.removeAttribute("noMatchesFound");
           this.clearTimer();
 
           if (aFireTextCommand)
@@ -831,6 +842,7 @@
           var str = this.value;
           this.currentSearchString = str;
           this.resultsPopup.selectedIndex = null;
+          this.removeAttribute("noMatchesFound");
           
           // We want to autocomplete only if the user is editing at the end of the text
           if (this.mInputElt.selectionEnd >= str.length)