fix index of appended items (broken by previous commit)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@34668 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/menu.cpp

@@ -385,8 +385,9 @@ bool wxMenu::DoInsertOrAppend(wxMenuItem *pItem, size_t pos)
     LPCTSTR pData = NULL;
     if ( pos == (size_t)-1 )
     {
-        // append at the end
+        // append at the end (note that the item is already appended to
-        pos = GetMenuItemCount();
+        // internal data structures)
+        pos = GetMenuItemCount() - 1;
     }
 
     BOOL ok = false;