1) ...seems like when this happens the right-click context menu does not come up in gnome-terminal, also.
2) installed lib11-6-dbg symbols:

(gdb) bt
#0  0x00007f81515ac45d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f814e037b72 in poll (__timeout=-1, __nfds=1, __fds=0x7fff4a855a10)
    at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0x157a930, cond=cond@entry=0x157a970, 
    vector=vector@entry=0x0, count=count@entry=0x0)
    at ../../src/xcb_conn.c:447
#3  0x00007f814e03964f in xcb_wait_for_event (c=0x157a930)
    at ../../src/xcb_in.c:622
#4  0x00007f8154ceb3a8 in _XReadEvents (dpy=dpy@entry=0x1577930)
    at ../../src/xcb_io.c:401
#5  0x00007f8154cd3889 in XIfEvent (dpy=0x1577930, event=0x7fff4a855c40, 
    predicate=0x7f8154d19f70 <_CheckCMEvent>, 
    arg=0x16a5800 "\240E\376T\201\177") at ../../src/IfEvent.c:68
#6  0x00007f8154d1a6e7 in _XimXRead (im=0x16a5800, 
    recv_buf=0x7fff4a856850 "", buf_len=2048, ret_len=0x7fff4a855d6c)
    at ../../../../modules/im/ximcp/imTrX.c:476
#7  0x00007f8154d1b317 in _XimReadData (im=im@entry=0x16a5800, 
    len=len@entry=0x7fff4a855dce, buf=buf@entry=0x7fff4a856850 "", 
    buf_size=buf_size@entry=2048)
    at ../../../../modules/im/ximcp/imTransR.c:165
#8  0x00007f8154d1b5f1 in _XimRead (im=im@entry=0x16a5800, 
    len=len@entry=0x7fff4a855e5e, buf=buf@entry=0x7fff4a856850 "", 
---Type <return> to continue, or q <return> to quit---
    buf_size=buf_size@entry=2048, 
    predicate=predicate@entry=0x7f8154d094d0 <_XimSetICValuesCheck>, 
    arg=arg@entry=0xc348b0 "@E\376T\201\177")
    at ../../../../modules/im/ximcp/imTransR.c:235
#9  0x00007f8154d0a1a6 in _XimProtoSetICValues (xic=0xc348b0, 
    arg=<optimized out>) at ../../../../modules/im/ximcp/imDefIc.c:778
#10 0x00007f8154cf80ad in XSetICValues (ic=0xc348b0)
    at ../../../src/xlibi18n/ICWrap.c:332
#11 0x00000000004cf585 in ?? ()
#12 0x00000000004be352 in ?? ()
#13 0x0000000000459c22 in ?? ()
#14 0x00000000004bccdc in ?? ()
#15 0x000000000041de46 in ?? ()
#16 0x000000000041f11b in ?? ()
#17 0x000000000042147d in ?? ()
#18 0x000000000045296c in ?? ()
#19 0x00000000004f49e1 in ?? ()
#20 0x00000000004f615f in ?? ()
#21 0x00000000004f7ed0 in ?? ()
#22 0x000000000055aaa7 in ?? ()
#23 0x00000000004ea3ee in ?? ()
#24 0x000000000055a98b in ?? ()
---Type <return> to continue, or q <return> to quit---
#25 0x00000000004ee9f7 in ?? ()
#26 0x00000000004eed10 in ?? ()
#27 0x0000000000418509 in ?? ()
#28 0x00007f81514ddec5 in __libc_start_main (main=0x417ab0, argc=1, 
    argv=0x7fff4a858a38, init=<optimized out>, fini=<optimized out>, 
    rtld_fini=<optimized out>, stack_end=0x7fff4a858a28) at libc-start.c:287
#29 0x0000000000418fbe in ?? ()
(gdb) thread 2
[Switching to thread 2 (Thread 0x7f8145d49700 (LWP 23725))]
#0  0x00007f81515ac45d in poll () at ../sysdeps/unix/syscall-template.S:81
81	in ../sysdeps/unix/syscall-template.S
(gdb) bt
#0  0x00007f81515ac45d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f815545414c in g_main_context_poll (priority=2147483647, n_fds=1, 
    fds=0x7f813c0010c0, timeout=-1, context=0x16b5b10)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:4103
#2  g_main_context_iterate (context=context@entry=0x16b5b10, 
    block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:3803
#3  0x00007f815545425c in g_main_context_iteration (context=0x16b5b10, 
    may_block=1) at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:3869
#4  0x00007f8145d5127d in ?? ()
   from /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
#5  0x00007f815547ab95 in g_thread_proxy (data=0x173f450)
    at /build/buildd/glib2.0-2.43.2/./glib/gthread.c:764
#6  0x00007f81518890a5 in start_thread (arg=0x7f8145d49700)
    at pthread_create.c:309
#7  0x00007f81515b690d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
(gdb) thread 3
[Switching to thread 3 (Thread 0x7f81475c7700 (LWP 23724))]
#0  0x00007f81515ac45d in poll () at ../sysdeps/unix/syscall-template.S:81
81	in ../sysdeps/unix/syscall-template.S
(gdb) bt
#0  0x00007f81515ac45d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f815545414c in g_main_context_poll (priority=2147483647, n_fds=2, 
    fds=0x7f81380010c0, timeout=-1, context=0x15aeb70)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:4103
#2  g_main_context_iterate (context=0x15aeb70, block=block@entry=1, 
    dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:3803
#3  0x00007f81554544d2 in g_main_loop_run (loop=0x15aeb00)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:4002
#4  0x00007f8155a47d56 in gdbus_shared_thread_func (user_data=0x15aeb40)
    at /build/buildd/glib2.0-2.43.2/./gio/gdbusprivate.c:273
#5  0x00007f815547ab95 in g_thread_proxy (data=0x13c0cf0)
    at /build/buildd/glib2.0-2.43.2/./glib/gthread.c:764
#6  0x00007f81518890a5 in start_thread (arg=0x7f81475c7700)
    at pthread_create.c:309
#7  0x00007f81515b690d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
(gdb) thread 4
[Switching to thread 4 (Thread 0x7f8148237700 (LWP 23723))]
#0  0x00007f81515ac45d in poll () at ../sysdeps/unix/syscall-template.S:81
81	in ../sysdeps/unix/syscall-template.S
(gdb) bt
#0  0x00007f81515ac45d in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f815545414c in g_main_context_poll (priority=2147483647, n_fds=1, 
    fds=0x7f81400008e0, timeout=-1, context=0x13bfeb0)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:4103
#2  g_main_context_iterate (context=context@entry=0x13bfeb0, 
    block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:3803
#3  0x00007f815545425c in g_main_context_iteration (context=0x13bfeb0, 
    may_block=may_block@entry=1)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:3869
#4  0x00007f8155454299 in glib_worker_main (data=<optimized out>)
    at /build/buildd/glib2.0-2.43.2/./glib/gmain.c:5614
#5  0x00007f815547ab95 in g_thread_proxy (data=0x13c0800)
    at /build/buildd/glib2.0-2.43.2/./glib/gthread.c:764
#6  0x00007f81518890a5 in start_thread (arg=0x7f8148237700)
    at pthread_create.c:309
#7  0x00007f81515b690d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111