scrollbar (no toolkit) display bug

[Raphaël Berbain]

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In GNU Emacs 21.1.1 (i686-pc-linux-gnu, X toolkit)
 of 2001-10-23 on jesus
configured using `configure  --prefix=/home/raph/local/emacs-21.1 
--with-x-toolkit=athena --with-xpm --with-jpeg --with-tiff --with-gif 
--with-png --without-toolkit-scroll-bars'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: nil
  default-enable-multibyte-characters: nil

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

For the bug to show up, I invoked emacs like this:

emacs -geometry 30x20 -q --no-site-file -l bug-report.el

bug-report.el contains:

,----[ bug-report.el ]
| (add-to-list 'default-frame-alist '(scroll-bar-width . 12))
`----

Once the emacs window comes up, I typed C-x 3.  I can then notice two
vertical bands where the toolbar isn't drawn properly, lined up with
the scrollbars.

Also, I can see a display glitch near the bottom left corner, where
the modeline has not be cleaned up along the scrollbar.  With this
geometry, the initial message in the echo area takes up more than one
line.  Once I type something, the welcome message disappears, the echo
area goes back to one line, but the left part (near the scrollbar) of
the modeline stays there.

I also noticed this bug appears when the toolbar isn't there.  The
vertical bands erase any text that happens to be there on a window
above a scrollbar.

There's a screenshot available at:

http://raphael.berbain.free.fr/emacs/screenshot.png

I saw this happening in 21.0.104, .105, .106 and 21.1.

Recent input:
<down> <down> L <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<up> <up> <up> C-u , <down> <down> <down> <down> <down> 
<down> <down> <up> <return> q <up> <up> C-u m C-x 5 
2 <switch-frame> M-x r e p o <tab> r <tab> <return
>

Recent messages:
Generating summary...done
Loading mule-util...done
Loading gnus-salt...done
Loading gnus-async...done
Loading mailabbrev...done
Loading message-utils...done
Loading bbdb-com...done
Making completion list...
Loading view...done
Loading emacsbug...done

-- 
Raphaël