diff --git a/checkin_notes b/checkin_notes
index 3d437c5d6d..8c2e2deae6 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -7557,7 +7557,7 @@ David  18 Sept 2008
 	clientgui/
 		AsyncRPC.cpp,h
 
-Charlie 18 Sep 2008
+Charlie 19 Sep 2008
     Mgr: The system handles timer events during modal dialogs, such as 
         while the RPC Wait dialog is shown. This may cause unintended 
         recursion and repeatedly posting the same RPC requests from 
@@ -7567,3 +7567,4 @@ Charlie 18 Sep 2008
     clientgui/
         BOINCBaseFrame.cpp
         MainDocument.cpp,.h
+        sg_BoincSimpleGUI.cpp
diff --git a/clientgui/sg_BoincSimpleGUI.cpp b/clientgui/sg_BoincSimpleGUI.cpp
index 59d0c57289..54e954e03c 100644
--- a/clientgui/sg_BoincSimpleGUI.cpp
+++ b/clientgui/sg_BoincSimpleGUI.cpp
@@ -547,6 +547,13 @@ void CSimplePanel::OnProjectsAttachToProject() {
 // called from CSimpleFrame::OnRefreshView()
 void CSimplePanel::OnFrameRender() {
     CMainDocument*    pDoc = wxGetApp().GetDocument();
+    wxASSERT(pDoc);
+
+    // OnFrameRender() may be called while SimpleGUI initialization is 
+    // in progress due to completion of a periodic get_messages RPC, 
+    // causing unintended recursion in CMainDocument::RequestRPC().  
+    // Check for that situation here.
+    if (pDoc->WaitingForRPC()) return;
 
     if (IsShown()) {