Re: mouse-face redisplay messy on Windows XP x64 Edition

[Michael Mauger]

John Paul Wallington writes:

> 
> I've noticed a weird redisplay bug on Emacs built and run with mingw
> on Windows XP x64 Edition for development versions of Emacs built on
> 2006-09-30 through 2006-10-14.
> 
> In a Gnus Summary buffer, mouse-wheel scrolling up and down over
> Author's names causes fragments of the highlight mouse-face to remain
> after the mouse cursor has left them.
> 
> Here's an example screenshot:
> http://www.shootybangbang.com/redisplay-mouse-face-bug.png
> 

I've seen the same thing on W32 on recent CVS checkout over the last month or 
so (current version: GNU Emacs 22.0.50.1 (i386-mingw-nt5.1.2600) of 2006-09-30, 
but I had seen it on a 2006-09-04 checkout as well).  

I see it most commonly in SQL interactive buffers, and can duplicate in simple 
shell buffers.  

Here's a recipe:

1) emacs -Q
2) M-x shell
3) (assuming DOS CMD shell here)
   ( C-j
   copy nul nul C-j
   copy nul nul C-j
   copy nul nul C-j
   ) RET

   Under a cygwin bash buffer I used:
   cat >/dev/null <<eof C-j
   This is a test C-j
   and this is more text. C-j
   This is a test C-j
   and this is more text. C-j
   This is a test C-j
   and this is more text. C-j
   eof RET

4) M-p RET (to repeat the command, repeat several times until window scrolls)
5) Position mouse cursor over a previous entered command, lines should highlight
6) M-p (some of the mouse highlight scrolls, but some got erased)
7) RET (some stray mouse highlight may still be seen depending on the number of 
lines in the command and the window height)

As I said, the problem occurs in the SQL interactive buffers (interactive 
session with a SQL interpreter).  It's more obvious there because multi line 
commands are common.   It's more obvious with commands that are near the size 
of the window and whose output does not scroll the command off the window (such 
as queries that return no rows).

Hope this helps.