In rtl mode, we must not just reverse the children,
but also allocate from the right. Use the newly introduced
box gadget api to achieve this.
https://bugzilla.gnome.org/show_bug.cgi?id=762945
GtkCheckButtonPrivate *priv = gtk_check_button_get_instance_private (GTK_CHECK_BUTTON (widget));
gtk_box_gadget_reverse_children (GTK_BOX_GADGET (priv->gadget));
+ gtk_box_gadget_set_allocate_reverse (GTK_BOX_GADGET (priv->gadget),
+ gtk_widget_get_direction (widget) == GTK_TEXT_DIR_RTL);
GTK_WIDGET_CLASS (gtk_check_button_parent_class)->direction_changed (widget, previous_direction);
}