bug#23690: 25.0.94; Window resizing regression

[Stephen Berman <stephen.berman@gmx.net>]

On Sat, 04 Jun 2016 13:53:47 +0300 Eli Zaretskii <eliz@gnu.org> wrote:

>> Date: Sat, 04 Jun 2016 11:48:24 +0200
>> From: martin rudalics <rudalics@gmx.at>
>> Cc: 23690@debbugs.gnu.org
>> 
>>  >> Would the attached patch fix it for you?
>>  >
>>  > It does indeed; thanks!
>> 
>> I'd very much like to push this to the release branch.  As it stands,
>> the behavior of this is botched on Lucid and Motif which both put the
>> scroll bar on left by default.  Eli?
>
> You'll have to convince me.  It sounds like the problem is triggered
> by a combination of 2 unlikely events, so I'm unsure why we should
> risk last-minute problems.

It is a regression from 24.5 (and earlier).  It is also documented in
(emacs)Mode Line Mouse: "Furthermore, by clicking and dragging ‘mouse-1’
on the divider between two side-by-side mode lines, you can move the
vertical boundary to the left or right."  On the other hand there's also
window-divider-mode, which is new in 25.1 provides the full behavior
that is currently missing due to this bug; however, it is not enabled by
default.  But if the fix is safe (it seems so to me, but I'm not
familiar enough with the code to be certain), I would like it in 25.1.
(I use the Gtk+ toolkit but also have the scroll bar on the left).

Steve Berman