diff --git a/src/msw/window.cpp b/src/msw/window.cpp
index 7dfd87df99..b5cd8d1f6f 100644
--- a/src/msw/window.cpp
+++ b/src/msw/window.cpp
@@ -755,6 +755,11 @@ wxWindowMSW::MSWShowWithEffect(bool show,
     if ( !s_pfnAnimateWindow )
         return Show(show);
 
+    // Show() has a side effect of sending a WM_SIZE to the window, which helps
+    // ensuring that it's laid out correctly, but AnimateWindow() doesn't do
+    // this so send the event ourselves
+    SendSizeEvent();
+
     // prepare to use AnimateWindow()
 
     if ( !timeout )