Crash on plugin unload

[bodqhrohro]

#0  g_type_check_instance_cast
    (type_instance=0x5555636ba640, iface_type=iface_type@entry=0x5555556da410 [GtkWidget/GtkObject/GInitiallyUnowned])
    at ../../../gobject/gtype.c:4060
#1  0x00007ffff16d9f00 in pwm_set_conv_menus_visible (gtkblist=gtkblist@entry=0x555555ade600, visible=visible@entry=0) at merge.c:408
#2  0x00007ffff16da14b in pwm_split_conversation (gtkblist=0x555555ade600) at merge.c:232
#3  0x00007ffff16da3b9 in plugin_unload (plugin=<optimized out>) at plugin.c:291
#4  0x00007ffff7172e7f in purple_plugin_unload (plugin=plugin@entry=0x5555557a1420) at ././libpurple/plugin.c:685
#5  0x00007ffff71731d2 in purple_plugins_unload (type=type@entry=PURPLE_PLUGIN_STANDARD) at ././libpurple/plugin.c:1250
#6  0x00007ffff71539a3 in purple_core_quit () at ././libpurple/core.c:224
#10 0x00007ffff738fedf in <emit signal ??? on instance 0x555566e1b4a0 [GtkImageMenuItem]>
    (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../../../gobject/gsignal.c:3554
    #7  0x00007ffff7370fd2 in g_closure_invoke
    (closure=0x555566d93980, return_value=0x0, n_param_values=1, param_values=0x7fffffffb1e0, invocation_hint=0x7fffffffb160)
    at ../../../gobject/gclosure.c:810
    #8  0x00007ffff7384784 in signal_emit_unlocked_R
    (node=node@entry=0x55555573f3a0, detail=detail@entry=0, instance=instance@entry=0x555566e1b4a0, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7fffffffb1e0) at ../../../gobject/gsignal.c:3742
    #9  0x00007ffff738f54f in g_signal_emit_valist
    (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7fffffffb390)
@--Type <RET> for more, q to quit, c to continue without paging--
    at ../../../gobject/gsignal.c:3498
#11 0x00007ffff787b7ba in gtk_widget_activate () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#12 0x00007ffff7776eed in gtk_menu_shell_activate_item () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#13 0x00007ffff77771b9 in  () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#14 0x00007ffff7764a8b in  () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#18 0x00007ffff738fedf in <emit signal ??? on instance 0x555563635780 [GtkMenu]>
    (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../../../gobject/gsignal.c:3554
    #15 0x00007ffff7370fd2 in g_closure_invoke
    (closure=0x5555556e2210, return_value=0x7fffffffb6d0, n_param_values=2, param_values=0x7fffffffb730, invocation_hint=0x7fffffffb6b0) at ../../../gobject/gclosure.c:810
    #16 0x00007ffff7383f06 in signal_emit_unlocked_R
    (node=<optimized out>, detail=detail@entry=0, instance=instance@entry=0x555563635780, emission_return=emission_return@entry=0x7fffffffb850, instance_and_params=instance_and_params@entry=0x7fffffffb730) at ../../../gobject/gsignal.c:3780
    #17 0x00007ffff738f078 in g_signal_emit_valist
    (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7fffffffb900)
    at ../../../gobject/gsignal.c:3508
#19 0x00007ffff787c9e4 in  () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#20 0x00007ffff7762cbc in gtk_propagate_event () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#21 0x00007ffff77630b3 in gtk_main_do_event () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
@--Type <RET> for more, q to quit, c to continue without paging--
#22 0x00007ffff75d510c in  () at /usr/lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0
#23 0x00007ffff728660d in g_main_dispatch (context=0x555555684800) at ../../../glib/gmain.c:3309
#24 g_main_context_dispatch (context=context@entry=0x555555684800) at ../../../glib/gmain.c:3974
#25 0x00007ffff7286890 in g_main_context_iterate
    (context=0x555555684800, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4047
#26 0x00007ffff7286b63 in g_main_loop_run (loop=0x5555574dfbe0) at ../../../glib/gmain.c:4241
#27 0x00007ffff776212a in gtk_main () at /usr/lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#28 0x0000555555590970 in main (argc=<optimized out>, argv=<optimized out>) at ././pidgin/gtkmain.c:939