I get
-258359228
and
-258359240
once a menu is added.
Although a menubar derives from wx.Window it may or may not be an actual window in the native implementation. If not then calling things like GetSize will attempt to use an invalid handle and will just fail, leaving whatever memory garbage was already in the data objects it is trying to set.
···
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Robin Dunn
Software Craftsman http://wxPython.org Java give you jitters? Relax with wxPython!