diff --git a/mailnews/imap/public/nsIImapFlagAndUidState.idl b/mailnews/imap/public/nsIImapFlagAndUidState.idl
index 9e20c3d5464..7d7fc311f3e 100644
--- a/mailnews/imap/public/nsIImapFlagAndUidState.idl
+++ b/mailnews/imap/public/nsIImapFlagAndUidState.idl
@@ -37,7 +37,7 @@
 
 #include "nsISupports.idl"
 
-[scriptable, uuid(70378b9a-6480-11d3-a533-0060b0fc04b7)]
+[scriptable, uuid(d4ba3414-fe9e-436b-a01b-bd446e737d04)]
 interface nsIImapFlagAndUidState : nsISupports 
 {
   readonly attribute long numberOfMessages;
@@ -46,7 +46,7 @@ interface nsIImapFlagAndUidState : nsISupports
   void getMessageFlags(in long zeroBasedIndex, out unsigned short result);
   void setMessageFlags(in long zeroBasedIndex, in unsigned short flags);
   void expungeByIndex(in unsigned long zeroBasedIndex);
-  void addUidFlagPair(in unsigned long uid, in unsigned short flags);
+  void addUidFlagPair(in unsigned long uid, in unsigned short flags, in unsigned long zeroBasedIndex);
   void addUidCustomFlagPair(in unsigned long uid, in string customFlag);
   string getCustomFlags(in unsigned long uid); // returns space-separated keywords
   void reset(in unsigned long howManyLeft);
diff --git a/mailnews/imap/src/nsImapFlagAndUidState.cpp b/mailnews/imap/src/nsImapFlagAndUidState.cpp
index ae8875cb59d..44f185f9687 100644
--- a/mailnews/imap/src/nsImapFlagAndUidState.cpp
+++ b/mailnews/imap/src/nsImapFlagAndUidState.cpp
@@ -212,61 +212,27 @@ NS_IMETHODIMP nsImapFlagAndUidState::ExpungeByIndex(PRUint32 msgIndex)
 
 
 // adds to sorted list.  protects against duplicates and going past fNumberOfMessageSlotsAllocated  
-NS_IMETHODIMP nsImapFlagAndUidState::AddUidFlagPair(PRUint32 uid, imapMessageFlagsType flags)
+NS_IMETHODIMP nsImapFlagAndUidState::AddUidFlagPair(PRUint32 uid, imapMessageFlagsType flags, PRUint32 zeroBasedIndex)
 {
   if (uid == nsMsgKey_None) // ignore uid of -1
     return NS_OK;
   PR_CEnterMonitor(this);
+  if (zeroBasedIndex > fNumberOfMessagesAdded)
+    fNumberOfMessagesAdded = zeroBasedIndex + 1;
   // make sure there is room for this pair
   if (fNumberOfMessagesAdded >= fNumberOfMessageSlotsAllocated)
   {
     fNumberOfMessageSlotsAllocated += kImapFlagAndUidStateSize;
     fUids.SetSize(fNumberOfMessageSlotsAllocated);
     fFlags = (imapMessageFlagsType*) PR_REALLOC(fFlags, sizeof(imapMessageFlagsType) * fNumberOfMessageSlotsAllocated); // new imapMessageFlagsType[fNumberOfMessageSlotsAllocated];
+    if (!fFlags)
+      return NS_ERROR_OUT_OF_MEMORY;
   }
-  
-  // optimize the common case of placing on the end
-  if (!fNumberOfMessagesAdded || (uid > (PRUint32) fUids[fNumberOfMessagesAdded - 1]))
-  {	
-    fUids.SetAt(fNumberOfMessagesAdded, uid);
-    fFlags[fNumberOfMessagesAdded] = flags;
-    fNumberOfMessagesAdded++;
-    if (flags & kImapMsgDeletedFlag)
-      fNumberDeleted++;
-    PR_CExitMonitor(this);
-    return NS_OK;
-  }
-  
-  // search for the slot for this uid-flag pair
-  
-  PRInt32 insertionIndex = -1;
-  PRBool foundIt = PR_FALSE;
-  
-  GetMessageFlagsFromUID(uid, &foundIt, &insertionIndex);
-  // Hmmm, is the server sending back unordered fetch responses?
-  if (((PRUint32) fUids[insertionIndex]) != uid)
-  {
-    // shift the uids and flags to the right
-    for (PRInt32 shiftIndex = fNumberOfMessagesAdded; shiftIndex > insertionIndex; shiftIndex--)
-    {
-      fUids.SetAt(shiftIndex, fUids[shiftIndex - 1]);
-      fFlags[shiftIndex] = fFlags[shiftIndex - 1];
-    }
-    fFlags[insertionIndex] = flags;
-    fUids.SetAt(insertionIndex, uid);
-    fNumberOfMessagesAdded++;
-    if (fFlags[insertionIndex] & kImapMsgDeletedFlag)
-      fNumberDeleted++;
-  }
-  else 
-  {
-    if ((fFlags[insertionIndex] & kImapMsgDeletedFlag) && !(flags & kImapMsgDeletedFlag))
-      fNumberDeleted--;
-    else
-      if (!(fFlags[insertionIndex] & kImapMsgDeletedFlag) && (flags & kImapMsgDeletedFlag))
-        fNumberDeleted++;
-      fFlags[insertionIndex] = flags;
-  }
+
+  fUids.SetAt(zeroBasedIndex, uid);
+  fFlags[zeroBasedIndex] = flags;
+  if (flags & kImapMsgDeletedFlag)
+    fNumberDeleted++;
   PR_CExitMonitor(this);
   return NS_OK;
 }
diff --git a/mailnews/imap/src/nsImapMailFolder.cpp b/mailnews/imap/src/nsImapMailFolder.cpp
index 48d2a8cdcad..4fe9e107e8c 100644
--- a/mailnews/imap/src/nsImapMailFolder.cpp
+++ b/mailnews/imap/src/nsImapMailFolder.cpp
@@ -3985,7 +3985,7 @@ void nsImapMailFolder::FindKeysToDelete(const nsMsgKeyArray &existingKeys, nsMsg
        ((flags & kImapMsgDeletedFlag) && !showDeletedMessages) )
     {
       nsMsgKey doomedKey = existingKeys[keyIndex];
-      if ((PRInt32) doomedKey < 0 && doomedKey != nsMsgKey_None)
+      if ((PRInt32) doomedKey <= 0 && doomedKey != nsMsgKey_None)
         continue;
       else
         keysToDelete.Add(existingKeys[keyIndex]);
@@ -4023,7 +4023,7 @@ void nsImapMailFolder::FindKeysToAdd(const nsMsgKeyArray &existingKeys, nsMsgKey
       imapMessageFlagsType flags;
       flagState->GetMessageFlags(flagIndex, &flags);
       NS_ASSERTION(uidOfMessage != nsMsgKey_None, "got invalid msg key");
-      if (uidOfMessage != nsMsgKey_None && (showDeletedMessages || ! (flags & kImapMsgDeletedFlag)))
+      if (uidOfMessage && uidOfMessage != nsMsgKey_None && (showDeletedMessages || ! (flags & kImapMsgDeletedFlag)))
       {
         if (mDatabase)
         {
diff --git a/mailnews/imap/src/nsImapServerResponseParser.cpp b/mailnews/imap/src/nsImapServerResponseParser.cpp
index 1aade810486..59aca8a946d 100644
--- a/mailnews/imap/src/nsImapServerResponseParser.cpp
+++ b/mailnews/imap/src/nsImapServerResponseParser.cpp
@@ -1322,7 +1322,7 @@ void nsImapServerResponseParser::msg_fetch()
           if (CurrentResponseUID() && CurrentResponseUID() != nsMsgKey_None 
             && fCurrentLineContainedFlagInfo && fFlagState)
           {
-            fFlagState->AddUidFlagPair(CurrentResponseUID(), fSavedFlagInfo);
+            fFlagState->AddUidFlagPair(CurrentResponseUID(), fSavedFlagInfo, fFetchResponseIndex - 1);
             for (PRInt32 i = 0; i < fCustomFlags.Count(); i++)
               fFlagState->AddUidCustomFlagPair(CurrentResponseUID(), fCustomFlags.CStringAt(i)->get());
             fCustomFlags.Clear();