bug#18990: 25.0.50; Scroll bar display problems

[Jan D.]

Hi.

> 8 nov 2014 kl. 08:54 skrev Eli Zaretskii <eliz@gnu.org>:
> 
>> From: Stephen Berman <stephen.berman@gmx.net>
>> Date: Sat, 08 Nov 2014 00:00:20 +0100
>> 
>> Starting Emacs like this:
>> 
>> emacs -Q --eval "(progn (modify-all-frames-parameters '((scroll-bar-width . 
>> 7))) (custom-set-variables '(scroll-bar-mode (quote left))))"
>> 
>> the scroll bar is correctly display on the left, but its width is the
>> default, not the customized value, and it overlays the left fringe,
>> which is hence hidden.
>> 
>> If another X window is moved over the Emacs frame (at least the left
>> side including the scroll bar), the left fringe becomes visible (only
>> partly if the other X window is not moved across the whole height of the
>> fringe) and the scroll bar width is correspondingly narrower (I didn't
>> measure but it looks like the width specified above); see the attached
>> screen shot, which also shows the incorrect scroll bar width and hidden
>> left fringe in the top Emacs frame.  As soon as the lower Emacs frame
>> regains focus, the scroll bar returns to full width and overlays the
>> left fringe again.
>> 
>> Another display glitch conditioned by the above settings is that typing
>> until point or eol enters the right fringe causes the left fringe in
>> just the current line to become visible (and the scroll bar
>> correspondingly narrowed/truncated in that line); I have not succeeded
>> in getting a screen shot of this glitch.
>> 
>> These display problems do not happen when the scroll bar is either on
>> the right or has its default width.  They also don't happen with the
>> non-toolkit-scroll-bar build.  They do happen with 24.3, the earliest
>> version I currently have (I don't have a non-toolkit-scroll-bar build of
>> 24.4 at hand but I guess it also has the problems).  (I haven't noticed
>> these problems before, since I've been using non-toolkit-scroll-bar
>> builds for a long time, and only since the 24.4 release have switched to
>> the toolkit scroll bar on the trunk to be able to test the horizontal
>> scroll bar.)
> 
> Sounds like a GTK thing to me.  Does this happen if you use a
> different toolkit, like lucid or athena?

Some Gtk+ themes force a fixed width scrollbar, because they use bitmaps.
Emacs can set scroll bar width all it wants, it wont matter to the Gtk+ scroll 
bar.
It is difficult to solve. 

        Jan D.