bug#44140: 26.3; ERC stamps: Really use latest buffer's window's width prior to `fill-column'

[Olivier Certner <olivier.certner@free.fr>]

Hi JP,

> I'm a little fuzzy on how the ALL-FRAMES = t param for the function
> `get-buffer-window' works exactly. The windows within each frame should
> follow the normal cyclic ordering (right?). But I think I learned
> somewhere that frame ordering is different and isn't affected by
> whichever one was last selected. If true, I suppose frame users (not me)
> are already used to this behavior and won't be surprised by it.

After reading some code (in "window.c"), I think `get-buffer-window' works 
like this:
1. It browses all windows in cyclic order (including windows of other frames 
or not, depending on the ALL-FRAMES parameter).
2. If the currently selected window contains the wanted buffer, it is returned 
immediately.
3. If 2 never occurs, and there is a window containing the current buffer in 
the selected frame, then the first one (i.e., the most recently activated) is 
returned.
4. If 2 and 3 never occur, than the first window containing the current buffer 
is returned (so, a window from another frame).
 
> Anyway, I happened upon another approach for the final display part (see
> attached sketch). If you see anything useful, just take it. Otherwise,
> sorry for the distraction.

Your changes seem interesting. I'm not very familiar with display properties, 
and I'm wondering if this would work as expected on text displays. Since I 
don't have much time to test that, and since these changes are independent of 
the bugs fixed here, I'd suggest to put them in a separate report.

Regards.

-- 
Olivier Certner