Gtk::Button not actionable?

[ax487 <ax487 gmx de>]

Hello all,

I noticed an odd discrepancy between gtk and gtkmm recently: It seems
that the GtkButton in gtk3 implements the GtkActionable interface,
meaning that I could attach use `gtk_actionable_set_action_name` to
attach a GAction to it. However, the gtkmm version, Gtk::Button does not
inherit from Gtk::Actionable. Therefore the functionality is not
available. There is a TODO in button.h:

//TODO: Derive from (and implement) Actionable when we can break ABI.

What does that mean? I thought that gtk3 and gtkmm3 were kept in sync,
i.e. gtkmm3-3.14 would be feature-complete regarding gkt3-3.14? Is this
functionality going to be implemented (when)?

References:

GtkButton :
https://developer.gnome.org/gtk3/stable/GtkButton.html

GtkActionable:
https://developer.gnome.org/gtk3/stable/GtkActionable.html

Gtk::Button :
https://developer.gnome.org/gtkmm/stable/classGtk_1_1Button.html
Gtk::Actionable :
https://developer.gnome.org/gtkmm/stable/classGtk_1_1Actionable.html

ax487