Sets the border width of the container.
The border width of a container is the amount of space to leave
around the outside of the container. The only exception to this is
GtkWindow; 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 gtk_widget_set_size_request()
to give it a size, and place it on the side of the container as
a spacer.
Sets the border width of the container. The border width of a container is the amount of space to leave around the outside of the container. The only exception to this is GtkWindow; 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 gtk_widget_set_size_request() to give it a size, and place it on the side of the container as a spacer.