new crash on leaving a message

[Jack <ostroffjh users sourceforge net>]

I have a message I just received, which I have no trouble viewing, but  
as soon as I leave the message (deleting, selecting another message,  
selecting another mailbox) balsa crashes.  Strace ends with:

clock_gettime(CLOCK_MONOTONIC, {2378793, 752194449}) = 0
recvmsg(7, 0x7ffe09ee81e0, 0)           = -1 EAGAIN (Resource  
temporarily unavailable)
poll([{fd=3, events=POLLIN}, {fd=7, events=POLLIN}, {fd=9,  
events=POLLIN}, {fd=11, events=POLLIN}, {fd=13, events=POLLIN}, {fd=15,  
events=POLLIN}], 6, 0) = 0 (Timeout)
write(6, "\1\0\0\0\0\0\0\0", 8)         = 8
futex(0x8c9c10, FUTEX_WAKE_PRIVATE, 1)  = 1
futex(0x8c6970, FUTEX_WAKE_PRIVATE, 1)  = 1
futex(0x8bd058, FUTEX_WAKE_PRIVATE, 1)  = 1
gettimeofday({1471884318, 459520}, NULL) = 0
gettimeofday({1471884318, 460986}, NULL) = 0
gettimeofday({1471884318, 461770}, NULL) = 0
gettimeofday({1471884318, 462068}, NULL) = 0
write(19, "\1\0\0\0\0\0\0\0", 8)        = 8
futex(0x10b5400, FUTEX_WAKE_PRIVATE, 1) = 1
futex(0x7fbb249fd638, FUTEX_WAIT_PRIVATE, 2, NULL) = -1 EAGAIN  
(Resource temporarily unavailable)
futex(0x7fbb249fd638, FUTEX_WAKE_PRIVATE, 1) = 0
write(2, "\n(balsa:19050): gtkhtml-CRITICAL"..., 98
(balsa:19050): gtkhtml-CRITICAL **: html_engine_unrealize: assertion  
'HTML_IS_ENGINE (e)' failed
) = 98
write(2, "\n(balsa:19050): Gtk-CRITICAL **:"..., 114
(balsa:19050): Gtk-CRITICAL **: gtk_im_context_set_client_window:  
assertion 'GTK_IS_IM_CONTEXT (context)' failed
) = 114
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x180} ---
+++ killed by SIGSEGV +++

The clock_gettime, recvmsg, poll, write, futex messages I see lots of  
earlier in the trace.

Balsa is compiled from git, gtk3 branch, with gtkmthm 4.10.0.  I  
suppose I'll reinstall webkit-gtk, but that's a long compile, and I'm  
leaving on vacation tomorrow, so I doubt I can troubleshoot much before  
I get home.  I was able to manually edit the mbox file, and move the  
bad message to its own file, so I can keep working.

The odd thing about the message is that it's rather short, with
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: base64
and the unencoded content being essentially "<p>message about a  
successful bill payment</p>" where the message is only one line, 118  
characters, with no non-printable or other strange characters.

I can try downgrading gtkhtml from 4.10.0 to 4.8.5 to see if it  
matters, but I just don't understand why the crash is on leaving the  
message, not on displaying it.  By the way, "display source" works  
fine, and closing the source window is also OK.  Not sure what else I  
can try, in terms of debugging.

As always, thanks for any suggestions.

Jack