-\pythonnote{The wxPython version of the \tt{wxMenu} constructor
-doesn't accept the callback argument because of reference counting
-issues. There is a specialized wxMenu constructor called
-\tt{wxPyMenu} which does and can be used for PopupMenus when callbacks
-are needed. You must retain a reference to the menu while useing it
-otherwise your callback function will get dereferenced when the menu
-does.
-}