Scrollbar crash on 21.2.28, Solaris 2.7

I had just opened up a compose window from VM and noticed the scrollbar was missing. Pressing Ctrl-L (several times) didn't help bring it to life. I ignored it and continued composing a message. Shortly thereafter, xemacs crashed. The C traceback is appended. If it matters, here's what's in instance: (gdb) p *instance $2 = {next = 0x0, mirror = 0x1e4eb40, scrollbar_is_active = 1 '\001', scrollbar_instance_changed = 0 '\000', scrollbar_data = 0x1da5d80} (gdb) p *instance->mirror $4 = {frame = 0x145cc00, next = 0x1e4ec80, hchild = 0x0, vchild = 0x0, current_display_lines = 0x122e3c0, desired_display_lines = 0x122e000, buffer = 0x1191000, scrollbar_vertical_instance = 0x12ce870, scrollbar_horizontal_instance = 0x12ceef0, subwindows_being_displayed = 0, truncate_win = 0} Ray #0 0xfeb96870 in _libc_kill () from /usr/lib/libc.so.1 #1 0xa8f14 in fatal_error_signal (sig=11) at emacs.c:272 #2 <signal handler called> #3 0xfeb36c5c in strlen () from /usr/lib/libc.so.1 #4 0xfeb7ec20 in _doprnt () from /usr/lib/libc.so.1 #5 0xfeb8086c in snprintf () from /usr/lib/libc.so.1 #6 0xfef4b308 in _XtDefaultErrorMsg () from /usr/openwin/lib/libXt.so.4 #7 0xfef4b4d4 in XtErrorMsg () from /usr/openwin/lib/libXt.so.4 #8 0xfef321f0 in _XtWindowedAncestor () from /usr/openwin/lib/libXt.so.4 #9 0xfef28018 in XtWidgetToApplicationContext () from /usr/openwin/lib/libXt.so.4 #10 0xfef370e4 in XtManageChildren () from /usr/openwin/lib/libXt.so.4 #11 0xfef3706c in XtManageChild () from /usr/openwin/lib/libXt.so.4 #12 0xd4d50 in x_update_scrollbar_instance_status (w=0x144b800, active=6872256, size=15, instance=0x12ce870) at scrollbar-x.c:264 #13 0xcb5a4 in update_window_scrollbars (w=0x144b800, mirror=0x1e4eb40, active=1, horiz_only=19720304) at scrollbar.c:293 #14 0x1bf2ec in redisplay_output_window (w=0x144b800) at redisplay-output.c:2227 #15 0x1b0750 in redisplay_window (window=21280768, skip_selected=220) at redisplay.c:6188 #16 0x1b0e3c in redisplay_frame (f=0x145cc00, preemption_check=268435456) at redisplay.c:6397 #17 0x1b1124 in redisplay_device (d=0x628c00, automatic=21351424) at redisplay.c:6475 #18 0x1b16a8 in redisplay_without_hooks () at redisplay.c:6564 #19 0x1b1924 in redisplay () at redisplay.c:6621 #20 0x107298 in Fnext_event (event=35602244, prompt=3143684) at event-stream.c:2238 #21 0x8af60 in Fcommand_loop_1 () at cmdloop.c:566 #22 0x8acbc in command_loop_1 (dummy=3143684) at cmdloop.c:490 #23 0xaf4e4 in condition_case_1 (handlers=2923520, bfun=0x8ac58 <command_loop_1>, barg=3143684, hfun=0x8b144 <cmd_error>, harg=3143684) at eval.c:1629 #24 0x8b254 in command_loop_2 (dummy=3143684) at cmdloop.c:252 #25 0xaf030 in internal_catch (tag=3225844, func=0x8b208 <command_loop_2>, arg=3143684, threw=0x0) at eval.c:1304 #26 0x8a4d0 in initial_command_loop (load_me=569864) at cmdloop.c:301 #27 0xaab28 in xemacs_21_2_b28_sparc_sun_solaris2_7 (argc=4, argv=0xffbeedd4, envp=0xffbeede8, restart=0) at emacs.c:1894 #28 0xab378 in main (argc=4, argv=0xffbeedd4, envp=0xffbeede8) at emacs.c:2320