diff --git a/include/wx/msw/mdi.h b/include/wx/msw/mdi.h
index 319d880da3..385659df1c 100644
--- a/include/wx/msw/mdi.h
+++ b/include/wx/msw/mdi.h
@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////////
-// Name:        mdi.h
+// Name:        wx/msw/mdi.h
 // Purpose:     MDI (Multiple Document Interface) classes
 // Author:      Julian Smart
 // Modified by:
@@ -121,7 +121,7 @@ private:
 class WXDLLEXPORT wxMDIChildFrame : public wxFrame
 {
 public:
-    wxMDIChildFrame();
+    wxMDIChildFrame() { Init(); }
     wxMDIChildFrame(wxMDIParentFrame *parent,
                     wxWindowID id,
                     const wxString& title,
@@ -130,6 +130,8 @@ public:
                     long style = wxDEFAULT_FRAME_STYLE,
                     const wxString& name = wxFrameNameStr)
     {
+        Init();
+
         Create(parent, id, title, pos, size, style, name);
     }
 
@@ -150,8 +152,10 @@ public:
     virtual void Restore();
     virtual void Activate();
 
-    // Handlers
+    // Implementation only from now on
+    // -------------------------------
 
+    // Handlers
     bool HandleMDIActivate(long bActivate, WXHWND, WXHWND);
     bool HandleWindowPosChanging(void *lpPos);
     bool HandleCommand(WXWORD id, WXWORD cmd, WXHWND control);
@@ -162,14 +166,22 @@ public:
 
     virtual void MSWDestroyWindow();
 
-    // Implementation
     bool ResetWindowStyle(void *vrect);
 
+    void OnIdle(wxIdleEvent& event);
+
 protected:
     virtual void DoGetPosition(int *x, int *y) const;
     virtual void DoSetClientSize(int width, int height);
     virtual void InternalSetMenuBar();
 
+    // common part of all ctors
+    void Init();
+
+private:
+    bool m_needsResize; // flag which tells us to artificially resize the frame
+
+    DECLARE_EVENT_TABLE()
     DECLARE_DYNAMIC_CLASS(wxMDIChildFrame)
 };
 
@@ -179,8 +191,6 @@ protected:
 
 class WXDLLEXPORT wxMDIClientWindow : public wxWindow
 {
-    DECLARE_DYNAMIC_CLASS(wxMDIClientWindow)
-
 public:
     wxMDIClientWindow() { Init(); }
     wxMDIClientWindow(wxMDIParentFrame *parent, long style = 0)
@@ -207,6 +217,7 @@ protected:
 
 private:
     DECLARE_EVENT_TABLE()
+    DECLARE_DYNAMIC_CLASS(wxMDIClientWindow)
 };
 
 #endif
diff --git a/include/wx/msw/window.h b/include/wx/msw/window.h
index 20f6cbb2aa..72126d5668 100644
--- a/include/wx/msw/window.h
+++ b/include/wx/msw/window.h
@@ -161,6 +161,10 @@ public:
     wxWindow* GetWindowChild1(wxWindowID id);
     wxWindow* GetWindowChild(wxWindowID id);
 
+    // a MSW only function which sends a size event to the window using its
+    // current size - this has an effect of refreshing the window layout
+    void SendSizeEvent();
+
     // implementation from now on
     // --------------------------
 
diff --git a/src/msw/mdi.cpp b/src/msw/mdi.cpp
index ef6f8e502c..7b551b6a4d 100644
--- a/src/msw/mdi.cpp
+++ b/src/msw/mdi.cpp
@@ -132,6 +132,10 @@ BEGIN_EVENT_TABLE(wxMDIParentFrame, wxFrame)
     EVT_SYS_COLOUR_CHANGED(wxMDIParentFrame::OnSysColourChanged)
 END_EVENT_TABLE()
 
+BEGIN_EVENT_TABLE(wxMDIChildFrame, wxFrame)
+    EVT_IDLE(wxMDIChildFrame::OnIdle)
+END_EVENT_TABLE()
+
 BEGIN_EVENT_TABLE(wxMDIClientWindow, wxWindow)
     EVT_SCROLL(wxMDIClientWindow::OnScroll)
 END_EVENT_TABLE()
@@ -612,8 +616,9 @@ bool wxMDIParentFrame::MSWTranslateMessage(WXMSG* msg)
 // wxMDIChildFrame
 // ===========================================================================
 
-wxMDIChildFrame::wxMDIChildFrame()
+void wxMDIChildFrame::Init()
 {
+    m_needsResize = TRUE;
 }
 
 bool wxMDIChildFrame::Create(wxMDIParentFrame *parent,
@@ -1201,6 +1206,22 @@ void wxMDIClientWindow::DoSetSize(int x, int y, int width, int height, int sizeF
     }
 }
 
+void wxMDIChildFrame::OnIdle(wxIdleEvent& event)
+{
+    // MDI child frames get their WM_SIZE when they're constructed but at this
+    // moment they don't have any children yet so all child windows will be
+    // positioned incorrectly when they are added later - to fix this, we
+    // generate an artificial size event here
+    if ( m_needsResize )
+    {
+        m_needsResize = FALSE; // avoid any possibility of recursion
+
+        SendSizeEvent();
+    }
+
+    event.Skip();
+}
+
 // ---------------------------------------------------------------------------
 // non member functions
 // ---------------------------------------------------------------------------
diff --git a/src/msw/tbar95.cpp b/src/msw/tbar95.cpp
index ab94b91434..2a1a5e7ce1 100644
--- a/src/msw/tbar95.cpp
+++ b/src/msw/tbar95.cpp
@@ -108,10 +108,7 @@
 // private function prototypes
 // ----------------------------------------------------------------------------
 
-// send a dummy WM_SIZE to the given window: this is used to relayout the frame
-// which contains us
-static void SendResizeMessage(HWND hwnd);
-
+// adjust toolbar bitmap colours
 static void wxMapBitmap(HBITMAP hBitmap, int width, int height);
 
 // ----------------------------------------------------------------------------
@@ -270,7 +267,7 @@ wxToolBar::~wxToolBar()
     wxFrame *frame = wxDynamicCast(GetParent(), wxFrame);
     if ( frame && wxTopLevelWindows.Find(frame) )
     {
-        SendResizeMessage(GetHwndOf(frame));
+        frame->SendSizeEvent();
     }
 
     if ( m_hBitmap )
@@ -895,7 +892,7 @@ void wxToolBar::UpdateSize()
     wxFrame *frame = wxDynamicCast(GetParent(), wxFrame);
     if ( frame )
     {
-        SendResizeMessage(GetHwndOf(frame));
+        frame->SendSizeEvent();
     }
 }
 
@@ -1005,19 +1002,6 @@ long wxToolBar::MSWWindowProc(WXUINT nMsg, WXWPARAM wParam, WXLPARAM lParam)
 // private functions
 // ----------------------------------------------------------------------------
 
-static void SendResizeMessage(HWND hwnd)
-{
-    // don't change the size, we just need to generate a WM_SIZE
-    RECT r;
-    if ( !::GetWindowRect(hwnd, &r) )
-    {
-        wxLogLastError(_T("GetWindowRect"));
-    }
-
-    (void)::PostMessage(hwnd, WM_SIZE, SIZE_RESTORED,
-                        MAKELPARAM(r.right - r.left, r.bottom - r.top));
-}
-
 // These are the default colors used to map the bitmap colors to the current
 // system colors. Note that they are in BGR format because this is what Windows
 // wants (and not RGB)
diff --git a/src/msw/window.cpp b/src/msw/window.cpp
index 854cc01d92..4b7e7370d5 100644
--- a/src/msw/window.cpp
+++ b/src/msw/window.cpp
@@ -3061,6 +3061,19 @@ bool wxWindow::HandleGetMinMaxInfo(void *mmInfo)
     return rc;
 }
 
+// generate an artificial resize event
+void wxWindow::SendSizeEvent()
+{
+    RECT r;
+    if ( !::GetWindowRect(GetHwnd(), &r) )
+    {
+        wxLogLastError(_T("GetWindowRect"));
+    }
+
+    (void)::PostMessage(GetHwnd(), WM_SIZE, SIZE_RESTORED,
+                        MAKELPARAM(r.right - r.left, r.bottom - r.top));
+}
+
 // ---------------------------------------------------------------------------
 // command messages
 // ---------------------------------------------------------------------------