It's possible to disable the automatic mnemonic conversion in the
UIManager/Action? Otherwise it's not possible to put text with an
undersocre into the menu. I searched in the gtkmm and gtk documentation
but don't found anything related to the mnemonic conversion in
UIManager/Action.
I've had the same problem with dynamically-generated menu names and
TreeView column titles. I think that "_" can be escaped as "__" but I
haven't tried it yet. It really should be documented, for instance here:
http://developer.gnome.org/doc/API/2.4/gtk/GtkAction.html