Turns out that I'm still able to reproduce the bug. However, I'm not able to get a core dump (or crash report) from the application. Just running OOo causes the internal SIGSEGV/SIGABRT handler to be called, which obviously prevents the application from dumping its core (which would cause the kernel to call apport). Calling OOo with the -norestore option seems to disable this behavior, but for some reason it still doesn't dump its core.

Manually producing a core dump using GDB and feeding it into apport doesn't work either since apport apparently couldn't retrieve the assertion error message(?).

I'm willing to research the issue further (although I have limited time to spare at the moment), but _please_ research issues better before coming up with further useless instructions. I've included the stack trace from GDB, it should help. I'm starting to believe that this is really a GTK bug.

I still get the same assertion:
Gtk:ERROR:/build/buildd/gtk+2.0-2.20.1/gtk/gtkfilesystemmodel.c:746:gtk_file_system_model_sort: assertion failed: (r == n_visible_rows)

GDB produces the following:
#0  0x00007ffff6c73a75 in *__GI_raise (sig=<value optimized out>)
    at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#1  0x00007ffff6c775c0 in *__GI_abort () at abort.c:92
#2  0x00007fffed04fbb4 in g_assertion_message () from /lib/libglib-2.0.so.0
#3  0x00007fffed050130 in g_assertion_message_expr ()
   from /lib/libglib-2.0.so.0
#4  0x00007fffee363846 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#5  0x00007fffee364ae8 in ?? () from /usr/lib/libgtk-x11-2.0.so.0
#6  0x00007fffeb081ec8 in ?? () from /usr/lib/libgio-2.0.so.0
#7  0x00007fffed0298c2 in g_main_context_dispatch ()
   from /lib/libglib-2.0.so.0
#8  0x00007fffed02d748 in ?? () from /lib/libglib-2.0.so.0
#9  0x00007fffed02dc55 in g_main_loop_run () from /lib/libglib-2.0.so.0
#10 0x00007fffee32d52b in gtk_dialog_run () from /usr/lib/libgtk-x11-2.0.so.0
#11 0x00007fffd21d3e50 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/fps_gnome.uno.so
#12 0x00007fffd21dbca8 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/fps_gnome.uno.so
#13 0x00007ffff563dee0 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#14 0x00007ffff563e0ea in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#15 0x00007ffff5643afc in ?? ()
---Type <return> to continue, or q <return> to quit---
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#16 0x00007ffff541b631 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#17 0x00007ffff55e7054 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#18 0x00007ffff55de97b in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#19 0x00007ffff55e287e in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#20 0x00007ffff55e2769 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#21 0x00007ffff561825a in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsfxlx.so
#22 0x00007ffff3833f38 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libvcllx.so
#23 0x00007fffecda42b8 in SalDisplay::DispatchInternalEvent() ()
   from /usr/lib/openoffice/basis3.2/program/libvclplug_genlx.so
#24 0x00007fffee8a74c0 in ?? ()
   from /usr/lib/openoffice/basis3.2/program/libvclplug_gtklx.so
#25 0x00007fffed0298c2 in g_main_context_dispatch ()
   from /lib/libglib-2.0.so.0
#26 0x00007fffed02d748 in ?? () from /lib/libglib-2.0.so.0
#27 0x00007fffed02d8fc in g_main_context_iteration ()
---Type <return> to continue, or q <return> to quit---
   from /lib/libglib-2.0.so.0
#28 0x00007fffee8a762d in ?? ()
   from /usr/lib/openoffice/basis3.2/program/libvclplug_gtklx.so
#29 0x00007ffff3652cae in Application::Yield(bool) ()
   from /usr/lib/openoffice/program/../basis-link/program/libvcllx.so
#30 0x00007ffff3652d27 in Application::Execute() ()
   from /usr/lib/openoffice/program/../basis-link/program/libvcllx.so
#31 0x00007ffff779c27f in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libsofficeapp.so
#32 0x00007ffff3657d99 in ?? ()
   from /usr/lib/openoffice/program/../basis-link/program/libvcllx.so
#33 0x00007ffff3657e85 in SVMain() ()
   from /usr/lib/openoffice/program/../basis-link/program/libvcllx.so
#34 0x00007ffff77d003c in soffice_main ()
   from /usr/lib/openoffice/program/../basis-link/program/libsofficeapp.so
#35 0x00000000004010bb in main ()