Re: Q on frame parameters *border-width

["Richard M. Stallman" <rms@gnu.org>]

    So, think I, perhaps you cannot change this parameter for an
    existing frame, but perhaps you can set it for
    `default-frame-alist' and it will then affect future frames. No
    such luck either.

It used to work, in the past, to set the border width for a new frame.
Perhaps it only works in a non-toolkit build.  Or perhaps modern window
managers don't allow the app to control this, while old ones did.

If someone could determine what the situation is, then we could
update the documentation to be clear about it.

    Both the doc string and the error message speak of the "window" border, so I
    guess this is a frame parameter that affects the border of each window in
    the frame.

They are mistaken.  The border belongs to the frame.

    Setting `internal-border-width' actually does change something, but it
    appears to be the internal _frame_ border, not a border around each window.

They are both for the frame.