fix menubar sizing (at least under windows)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@11882 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/univ/menu.cpp

@@ -1548,6 +1548,9 @@ void wxMenuBar::Attach(wxFrame *frame)
         SetCursor(wxCURSOR_ARROW);
 
         SetFont(wxSystemSettings::GetSystemFont(wxSYS_SYSTEM_FONT));
+
+        // calculate and set our height (it won't be changed any more)
+        SetSize(-1, GetBestSize().y);
     }
 
     // remember the last frame which had us to avoid unnecessarily reparenting