PanelMenu.Button is now a GObject subclass, so initialization must happen in _init() rather than constructor(). https://gitlab.gnome.org/GNOME/gnome-shell-extensions/issues/113
PanelMenu.Button is now a GObject subclass, so initialization must happen in _init() rather than constructor(). https://gitlab.gnome.org/GNOME/gnome-shell-extensions/issues/113