private void on_avatarButton_button_press_event(object o, Gtk.ButtonPressEventArgs args)
{
if (args.Event.Button == 3) {
Gtk.Menu menu = new Gtk.Menu ();
ImageMenuItem clearItem = new ImageMenuItem (Gtk.Stock.Clear, null);
clearItem.Activated += clearItem_Activated;
menu.Append (clearItem);
menu.ShowAll ();
menu.Popup ();
}
}