Bug 336831: Biff doesn't clear from system tray; r/sr=Neil

mailnews/base/src/nsMessengerWinIntegration.cpp

@@ -582,10 +582,12 @@ nsresult nsMessengerWinIntegration::AlertFinished()
   // okay, we are done showing the alert
   // now put an icon in the system tray, if allowed
   PRBool showTrayIcon = !mSuppressBiffIcon;
-  nsresult rv;
-  nsCOMPtr<nsIPrefBranch> prefBranch(do_GetService(NS_PREFSERVICE_CONTRACTID, &rv));
-  if (NS_SUCCEEDED(rv) && prefBranch)
+  if (showTrayIcon)
+  {
+    nsCOMPtr<nsIPrefBranch> prefBranch(do_GetService(NS_PREFSERVICE_CONTRACTID));
+    if (prefBranch)
       prefBranch->GetBoolPref(SHOW_TRAY_ICON_PREF, &showTrayIcon);
+  }
   if (showTrayIcon)
   {
     GenericShellNotify(NIM_ADD);