bug#37213: Execute set-window-margins. left-margin-width remains 0.

[martin rudalics]

> OK.  It seems there are two alternative strategies for manipulating a
> window's margins.  One is to use set-window-margins together with
> window-margins, the other is to use left/right-margin-width and
> set-window-buffer.

Right.  With fringes and scroll bars you can additionally set a frame
parameter.  I know that you're not interested in the latter but any
descriptions should be consistent.

>> Hmm...  What is the "current width of the left or right margin"?
>
> I'm not sure I understand the question.  In a given window with a left
> margin, there will be a maximum length of string which can be displayed
> in that margin.  That is its "current width".  The same for a right
> margin.  What are you getting at, here?

That you omitted the "In a given window" preamble in the manual.  When
you have a frame with two windows showing one and the same buffer, the
margins of these windows can have different widths.  What would be the
"current width" in that case?

martin