--- a/mailnews/imap/src/nsImapUrl.cpp
+++ b/mailnews/imap/src/nsImapUrl.cpp
@@ -1176,16 +1176,29 @@ NS_IMETHODIMP nsImapUrl::SetMockChannel(
 
 NS_IMETHODIMP nsImapUrl::GetAllowContentChange(PRBool *result)
 {
   NS_ENSURE_ARG_POINTER(result);
   *result = m_allowContentChange;
   return NS_OK;
 }
 
+NS_IMETHODIMP nsImapUrl::Clone(nsIURI **_retval)
+{
+  nsresult rv = nsMsgMailNewsUrl::Clone(_retval);
+  NS_ENSURE_SUCCESS(rv, rv);
+  // also clone the mURI member, because GetUri below won't work if
+  // mURI isn't set due to escaping issues.
+  nsCOMPtr <nsIMsgMessageUrl> clonedUrl = do_QueryInterface(*_retval);
+  if (clonedUrl)
+    clonedUrl->SetUri(mURI.get());
+  return rv;
+}
+
+
 NS_IMETHODIMP nsImapUrl::SetUri(const char * aURI)
 {
   mURI= aURI;
   return NS_OK;
 }
 
 NS_IMETHODIMP nsImapUrl::GetUri(char** aURI)
 {

--- a/mailnews/imap/src/nsImapUrl.h
+++ b/mailnews/imap/src/nsImapUrl.h
@@ -54,16 +54,17 @@ class nsImapUrl : public nsIImapUrl, pub
 {
 public:
 
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIURI override
   NS_IMETHOD SetSpec(const nsACString &aSpec);
   NS_IMETHOD SetQuery(const nsACString &aQuery);
+  NS_IMETHOD Clone(nsIURI **_retval);
 
   //////////////////////////////////////////////////////////////////////////////
   // we support the nsIImapUrl interface
   //////////////////////////////////////////////////////////////////////////////
   NS_DECL_NSIIMAPURL
 
   // nsIMsgMailNewsUrl overrides
   NS_IMETHOD IsUrlType(PRUint32 type, PRBool *isType);