b4n commented on this pull request.
@@ -6321,6 +6321,7 @@
<object class="GtkMenuBar" id="menubar1"> <property name="visible">True</property> <property name="can_focus">False</property> + <signal name="deactivate" handler="on_menubar1_deactivate" after="yes" swapped="no"/>
https://developer.gnome.org/gtk3/stable/GtkMenuShell.html#id-1.3.20.5.10.4 suggests using select/deselect is just fine. And in practice it does seem to work great. But agreed the docs are not very clear.