bug#26668: 11.90.2; separator in the toolbar remains vertical when I display toolbar on the left or right

[Sureyya Sahin]

Remember to cover the basics, that is, what you expected to happen and
what in fact did happen.

Be sure to consult the FAQ section in the manual before submitting
a bug report.  In addition check if the bug is reproducable with an
up-to-date version of AUCTeX.  So please upgrade to the version
available from http://www.gnu.org/software/auctex/ if your
installation is older than the one available from the web site.

If the bug is triggered by a specific (La)TeX file, you should try
to produce a minimal sample file showing the problem and include it
in your report.

Your report will be posted for the auctex package at the GNU bug
tracker.  Visit http://debbugs.gnu.org/cgi/pkgreport.cgi?pkg=auctex
to browse existing AUCTeX bugs.
------------------------------------------------------------------------

With latex-mode enabled (auctex), when I choose to display the toolbar
on the left side (or right side) vertically in emacs, the separator line
which separates the latex and preview buttons does not transform to
horizontal configuration. So, it remains vertical and occupy too much of
space; please also see the attached screenshot of the toolbar.

Emacs  : GNU Emacs 25.2.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.14.13)
 of 2017-04-23
Package: 11.90.2

current state:
==============
(setq
 AUCTeX-date "2017-04-21"
 window-system 'x
 LaTeX-version "2e"
 TeX-style-path '("~/.emacs.d/auctex"
                  "/home/ssahin/.emacs.d/elpa/auctex-11.90.2/style"
                  "/home/ssahin/.emacs.d/auctex/auto"
                  "/home/ssahin/.emacs.d/auctex/style" "auto" "style")
 TeX-auto-save t
 TeX-parse-self t
 TeX-master t
 TeX-command-list '(("TeX"
                     "%(PDF)%(tex) %(file-line-error) %(extraopts) 
%`%S%(PDFout)%(mode)%' %t"
                     TeX-run-TeX nil
                     (plain-tex-mode ams-tex-mode texinfo-mode) :help
                     "Run plain TeX")
                    ("LaTeX" "%`%l%(mode)%' %t" TeX-run-TeX nil
                     (latex-mode doctex-mode) :help "Run LaTeX")
                    ("Makeinfo" "makeinfo %(extraopts) %t"
                     TeX-run-compile nil (texinfo-mode) :help
                     "Run Makeinfo with Info output")
                    ("Makeinfo HTML" "makeinfo %(extraopts) --html %t"
                     TeX-run-compile nil (texinfo-mode) :help
                     "Run Makeinfo with HTML output")
                    ("AmSTeX"
                     "amstex %(PDFout) %(extraopts) %`%S%(mode)%' %t"
                     TeX-run-TeX nil (ams-tex-mode) :help "Run AMSTeX")
                    ("ConTeXt"
                     "%(cntxcom) --once --texutil %(extraopts) %(execopts)%t"
                     TeX-run-TeX nil (context-mode) :help
                     "Run ConTeXt once")
                    ("ConTeXt Full"
                     "%(cntxcom) %(extraopts) %(execopts)%t" TeX-run-TeX
                     nil (context-mode) :help
                     "Run ConTeXt until completion")
                    ("BibTeX" "bibtex %s" TeX-run-BibTeX nil t :help
                     "Run BibTeX")
                    ("Biber" "biber %s" TeX-run-Biber nil t :help
                     "Run Biber")
                    ("View" "%V" TeX-run-discard-or-function t t :help
                     "Run Viewer")
                    ("Print" "%p" TeX-run-command t t :help
                     "Print the file")
                    ("Queue" "%q" TeX-run-background nil t :help
                     "View the printer queue" :visible TeX-queue-command)
                    ("File" "%(o?)dvips %d -o %f " TeX-run-dvips t t
                     :help "Generate PostScript file")
                    ("Dvips" "%(o?)dvips %d -o %f " TeX-run-dvips nil t
                     :help "Convert DVI file to PostScript")
                    ("Dvipdfmx" "dvipdfmx %d" TeX-run-dvipdfmx nil t
                     :help "Convert DVI file to PDF with dvipdfmx")
                    ("Ps2pdf" "ps2pdf %f" TeX-run-ps2pdf nil t :help
                     "Convert PostScript file to PDF")
                    ("Glossaries" "makeglossaries %s" TeX-run-command
                     nil t :help
                     "Run makeglossaries to create glossary file")
                    ("Index" "makeindex %s" TeX-run-index nil t :help
                     "Run makeindex to create index file")
                    ("upMendex" "upmendex %s" TeX-run-index t t :help
                     "Run mendex to create index file")
                    ("Xindy" "texindy %s" TeX-run-command nil t :help
                     "Run xindy to create index file")
                    ("Check" "lacheck %s" TeX-run-compile nil
                     (latex-mode) :help
                     "Check LaTeX file for correctness")
                    ("ChkTeX" "chktex -v6 %s" TeX-run-compile nil
                     (latex-mode) :help
                     "Check LaTeX file for common mistakes")
                    ("Spell" "(TeX-ispell-document \"\")"
                     TeX-run-function nil t :help
                     "Spell-check the document")
                    ("Clean" "TeX-clean" TeX-run-function nil t :help
                     "Delete generated intermediate files")
                    ("Clean All" "(TeX-clean t)" TeX-run-function nil t
                     :help
                     "Delete generated intermediate and output files")
                    ("Other" "" TeX-run-command t t :help
                     "Run an arbitrary command")
                    )
 )

Screenshot of the toolbar with vertical separator.png
Description: PNG image