gtkContainerSetBorderWidth(object, border.width)objectborder.widthGtkWindow; because toplevel windows can't leave space outside,
they leave the space inside. The border is added on all sides of
the container. To add space to only one side, one approach is to
create a GtkAlignment widget, call gtkWidgetSetSizeRequest
to give it a size, and place it on the side of the container as
a spacer.