diff --git a/xpinstall/public/Makefile.in b/xpinstall/public/Makefile.in
index 275b4abbc4d8..4d06869dc3d5 100644
--- a/xpinstall/public/Makefile.in
+++ b/xpinstall/public/Makefile.in
@@ -34,6 +34,7 @@ MODULE		= xpinstall
 XPIDLSRCS	= \
 		nsIXPINotifier.idl \
 		nsIXPIProgressDlg.idl \
+        nsPIXPIProxy.idl \
 		nsPIXPIStubHook.idl \
 		nsPIXPIManagerCallbacks.idl \
 		$(NULL)
diff --git a/xpinstall/public/makefile.win b/xpinstall/public/makefile.win
index 6cd29403487c..69db50731523 100644
--- a/xpinstall/public/makefile.win
+++ b/xpinstall/public/makefile.win
@@ -36,6 +36,7 @@ XPIDLSRCS =                               \
             .\nsIXPIProgressDlg.idl       \
             .\nsPIXPIStubHook.idl         \
             .\nsPIXPIManagerCallbacks.idl \
+            .\nsPIXPIProxy.idl            \
 #            .\nsIUpdateNotification.idl   \
             $(NULL) 
 
diff --git a/xpinstall/public/nsPIXPIProxy.idl b/xpinstall/public/nsPIXPIProxy.idl
new file mode 100644
index 000000000000..d2d69eb0089b
--- /dev/null
+++ b/xpinstall/public/nsPIXPIProxy.idl
@@ -0,0 +1,37 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * The contents of this file are subject to the Mozilla Public
+ * License Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ *
+ * The Original Code is Mozilla Communicator client code, 
+ * released March 31, 1998. 
+ *
+ * The Initial Developer of the Original Code is Netscape Communications 
+ * Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998-2001 Netscape Communications Corporation. All
+ * Rights Reserved.
+ *
+ * Contributor(s): 
+ *     Daniel Veditz <dveditz@netscape.com>
+ */
+
+#include "nsISupports.idl"
+
+/**
+ * nsPIXPIProxy
+ *
+ * Used to handle miscellaneous things that XPInstall needs to perform
+ * over on the main UI thread.
+ */
+[scriptable,uuid(6F9D2890-167D-11d5-8DAF-000064657374)]
+interface nsPIXPIProxy : nsISupports
+{
+    void refreshPlugins(in nsISupports aWindow);
+};