As Andy reported, the main menu geometry is not correct after
my recent changes, as the application contents slide underneath
the menu bar. In fact the menu bar is just floating above
everything else.
So I've tried to move the menu to the framespace (as it should
belong to the frame), but the sizing algos for both the window
and the menu make some assumptions that render this task quite
difficult. Eventually I would like to be able to swallow the
menu somewhere else inside the border... but not right now.