bug#29279: Sharing the margins

[Dmitry Gutov <dgutov@yandex.ru>]

On 11/14/17 5:30 PM, Eli Zaretskii wrote:

>> So I'd personally prefer to have all padding on one side.
> 
> But then requests for the rightmost (or leftmost) column will go
> unsatisfied, for apparently no good reason.

It might be just a matter of interpretation: even if all the padding is 
on the right, the "rightmost" column will remain such, among all the 
visible columns.

Alternatively, the new function will be able to set the padding to 
"justify" as well, but I doubt a lot of users will like it.

>> Doesn't the use of the special area trigger the window configuration
>> changes as well, in similar situations?
> 
> No, and I still hope we can avoid the need to do that.
> tabulated-list-mode came close, but I eventually succeeded in making
> it happy with the other hooks.
>
>> After all, it also changes the accessible window body width, right?
> 
> It depends on your POV.  My POV is that it doesn't, since the window
> dimensions and the dimensions of the text area are unaltered.  At
> least one other person disagreed (vociferously).

But the effects are almost entirely the same, aren't they? Both the 
change of margin width and the change of line numbers column width force 
the reflowing of buffer contents display.

If the latter doesn't have to run window-configuration-change-hook, 
maybe the margin changes don't have to either, and "other hooks" will 
suffice as well?