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, use a specific
#GtkWidget:margin property on the child widget, for example
#GtkWidget:margin-top.
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, use a specific #GtkWidget:margin property on the child widget, for example #GtkWidget:margin-top.