On Tue, 2006-03-21 at 11:50 -0500, Steve Hall wrote:
I've seen this before, but can't reproduce it here on Windows. What
platform are you on?
Debian GNU/Linux.  Since my office mates (who all use Windows) haven't complained, I can only suppose they've never encountered it either (or alternatively, perhaps they don't use diff mode).  I'm using the "vim-full" Debian package for my gvim.

Versions of packages vim-full depends on:
ii  libart-2.0-2             2.3.17-1        Library of functions for 2D graphi
ii  libatk1.0-0              1.10.3-1        The ATK accessibility toolkit
ii  libbonobo2-0             2.10.1-1        Bonobo CORBA interfaces library
ii  libbonoboui2-0           2.10.1-2        The Bonobo UI library
ii  libc6                    2.3.6-3         GNU C Library: Shared libraries an
ii  libcairo2                1.0.2-3         The Cairo 2D vector graphics libra
ii  libfontconfig1           2.3.2-5         generic font configuration library
ii  libgconf2-4              2.12.1-12       GNOME configuration database syste
ii  libglib2.0-0             2.8.6-1         The GLib library of C routines
ii  libgnome-keyring0        0.4.8-1         GNOME keyring services library
ii  libgnome2-0          The GNOME 2 library - runtime file
ii  libgnomecanvas2-0        2.12.0-2        A powerful object-oriented display
ii  libgnomeui-0             2.12.1-1        The GNOME 2 libraries (User Interf
ii  libgnomevfs2-0           2.12.2-7        GNOME virtual file-system (runtime
ii  libgpmg1                 1.19.6-22       General Purpose Mouse - shared lib
ii  libgtk2.0-0              2.8.13-1        The GTK+ graphical user interface 
ii  libice6                  6.9.0.dfsg.1-4  Inter-Client Exchange library
ii  libncurses5              5.5-1           Shared libraries for terminal hand
ii  liborbit2                1:2.12.4-1      libraries for ORBit2 - a CORBA ORB
ii  libpango1.0-0            1.10.4-1        Layout and rendering of internatio
ii  libperl5.8               5.8.8-3         Shared Perl library
ii  libpopt0                 1.7-5           lib for parsing cmdline parameters
ii  libruby1.8               1.8.4-1         Libraries necessary to run Ruby 1.
ii  libsm6                   6.9.0.dfsg.1-4  X Window System Session Management
ii  libx11-6                 6.9.0.dfsg.1-4  X Window System protocol client li
ii  libxcursor1              1.1.3-1         X cursor management library
ii  libxext6                 6.9.0.dfsg.1-4  X Window System miscellaneous exte
ii  libxi6                   6.9.0.dfsg.1-4  X Window System Input extension li
ii  libxinerama1             6.9.0.dfsg.1-4  X Window System multi-head display
ii  libxml2                  2.6.23.dfsg.2-2 GNOME XML library
ii  libxrandr2               6.9.0.dfsg.1-4  X Window System Resize, Rotate and
ii  libxrender1              1:     X Rendering Extension client libra
ii  libxt6                   6.9.0.dfsg.1-4  X Toolkit Intrinsics
ii  python2.3                2.3.5-9.1       An interactive high-level object-o
ii  tcl8.4                   8.4.12-1        Tcl (the Tool Command Language) v8
ii  vim-gui-common           1:6.4-007+1     Vi IMproved - Common GUI files
ii  vim-runtime              1:6.4-007+1     Vi IMproved - Runtime files
ii  zlib1g                   1:1.2.3-11      compression library - runtime
I'll have to do some more exploring, it could be a GTK bug. It feels
similar to the known problem where hitting Enter with a dialog open
can crash/close vim.
OK.  The GTK version I'm using is shown above.