Crash when entering kanji from Kanjipad

[mpapushin]

Upon entering any character from kanjipad, program crashes with segfault. Character is written to text entry, but program crashes as kanjipad window closes.

Tested on gwaei 3.6.2-2, Arch Linux 4.12.13-1
Program outputs errors:
** (gwaei:32117): CRITICAL **: gw_spellcheck_queue: assertion 'priv->handle != NULL' failed

** (gwaei:32117): CRITICAL **: gw_spellcheck_queue: assertion 'priv->handle != NULL' failed

** (gwaei:32117): CRITICAL **: gw_spellcheck_queue: assertion 'priv->handle != NULL' failed

(gwaei:32117): GLib-GObject-WARNING **: invalid cast from 'GtkDrawingArea' to 'GwKanjipadWindow'

GDB output:
Thread 1 "gwaei" received signal SIGSEGV, Segmentation fault.
0x000055555558ac8f in ?? ()
(gdb) where
#0 0x000055555558ac8f in ()
#1 0x00007ffff602bead in g_closure_invoke () at /usr/lib/libgobject-2.0.so.0
#2 0x00007ffff603e4ae in () at /usr/lib/libgobject-2.0.so.0
#3 0x00007ffff6046c85 in g_signal_emit_valist () at /usr/lib/libgobject-2.0.so.0
#4 0x00007ffff6047b78 in g_signal_emit_by_name () at /usr/lib/libgobject-2.0.so.0
#5 0x00007ffff77889fc in () at /usr/lib/libgtk-3.so.0
#6 0x00007ffff778a5c8 in () at /usr/lib/libgtk-3.so.0
#7 0x00007ffff76f5f2b in () at /usr/lib/libgtk-3.so.0
#8 0x00007ffff602c0e6 in () at /usr/lib/libgobject-2.0.so.0
#9 0x00007ffff604693d in g_signal_emit_valist () at /usr/lib/libgobject-2.0.so.0
#10 0x00007ffff604769f in g_signal_emit () at /usr/lib/libgobject-2.0.so.0
#11 0x00007ffff78491c5 in () at /usr/lib/libgtk-3.so.0
#12 0x00007ffff76f4e70 in gtk_main_do_event () at /usr/lib/libgtk-3.so.0
#13 0x00007ffff71ff516 in () at /usr/lib/libgdk-3.so.0
#14 0x00007ffff7231a65 in () at /usr/lib/libgdk-3.so.0
#15 0x00007ffff5d53a57 in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#16 0x00007ffff5d53c88 in () at /usr/lib/libglib-2.0.so.0
#17 0x00007ffff5d53d1c in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#18 0x00007ffff630f72d in g_application_run () at /usr/lib/libgio-2.0.so.0
#19 0x0000555555576d29 in main ()