Either this is the top:
#0  0x00007fffefe025d0 in __pause_nocancel () at ../sysdeps/unix/syscall-template.S:82
#1  0x00007fffefdf89b8 in __pthread_mutex_lock_full (mutex=0x3232ab0) at pthread_mutex_lock.c:316

Sometimes this:
#0  __lll_lock_wait () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:132
#1  0x00007fffefdfd1c5 in _L_lock_883 () from /lib64/libpthread.so.0
#2  0x00007fffefdfd01a in __pthread_mutex_lock (mutex=0x31839c0) at pthread_mutex_lock.c:61

But the continuation is always the following:
#2  0x00007ffff0fb8ea1 in g_static_rec_mutex_lock () from /usr/lib64/libglib-2.0.so.0
#3  0x00007ffff6701094 in queue_repaint (this=0x3232c00) at mdc_canvas_view.cpp:884
#4  mdc::CanvasView::queue_repaint (this=0x3232c00) at mdc_canvas_view.cpp:872
#5  0x00007ffff66efeff in mdc::CanvasItem::~CanvasItem (this=0x3234490, __in_chrg=<optimized out>) at mdc_canvas_item.cpp:109
#6  0x00007ffff66e45c9 in mdc::AreaGroup::~AreaGroup (this=0x3234490, __in_chrg=<optimized out>) at mdc_area_group.cpp:48
#7  0x00007ffff671bb6e in mdc::Layer::~Layer (this=0x3234360, __in_chrg=<optimized out>) at mdc_layer.cpp:63
#8  0x00007ffff66e4c69 in mdc::BackLayer::~BackLayer (this=0x3234360, __in_chrg=<optimized out>) at mdc_back_layer.cpp:58
#9  0x00007ffff6700289 in mdc::CanvasView::~CanvasView (this=0x3232c00, __in_chrg=<optimized out>) at mdc_canvas_view.cpp:119
#10 0x00007ffff67077c9 in mdc::BufferedXlibCanvasView::~BufferedXlibCanvasView (this=0x3232c00, __in_chrg=<optimized out>) at mdc_canvas_view_x11.cpp:165
#11 0x00007ffff583cf03 in mdc::GtkCanvas::on_unrealize (this=0x3217580) at gtk/mdc_gtk_canvas_view.cpp:83
#12 0x00007ffff529698d in Gtk::Widget_Class::unrealize_callback(_GtkWidget*) () from /usr/lib64/libgtkmm-2.4.so.1
#13 0x00007ffff20c76dc in _g_closure_invoke_va () from /usr/lib64/libgobject-2.0.so.0
#14 0x00007ffff20dffe1 in g_signal_emit_valist () from /usr/lib64/libgobject-2.0.so.0
#15 0x00007ffff20e0ae2 in g_signal_emit () from /usr/lib64/libgobject-2.0.so.0
#16 0x00007ffff418aab2 in gtk_widget_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#17 0x00007ffff402ea1a in gtk_frame_forall () from /usr/lib64/libgtk-x11-2.0.so.0
#18 0x00007ffff520975a in Gtk::Container_Class::forall_vfunc_callback(_GtkContainer*, int, void (*)(_GtkWidget*, void*), void*) () from /usr/lib64/libgtkmm-2.4.so.1
#19 0x00007ffff4186d01 in gtk_widget_real_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#20 0x00007ffff529698d in Gtk::Widget_Class::unrealize_callback(_GtkWidget*) () from /usr/lib64/libgtkmm-2.4.so.1
#21 0x00007ffff20c76dc in _g_closure_invoke_va () from /usr/lib64/libgobject-2.0.so.0
#22 0x00007ffff20dffe1 in g_signal_emit_valist () from /usr/lib64/libgobject-2.0.so.0
#23 0x00007ffff20e0ae2 in g_signal_emit () from /usr/lib64/libgobject-2.0.so.0
#24 0x00007ffff418aab2 in gtk_widget_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#25 0x00007ffff3fbad5b in gtk_box_forall () from /usr/lib64/libgtk-x11-2.0.so.0
#26 0x00007ffff4186d01 in gtk_widget_real_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#27 0x00007ffff20c76dc in _g_closure_invoke_va () from /usr/lib64/libgobject-2.0.so.0
#28 0x00007ffff20dffe1 in g_signal_emit_valist () from /usr/lib64/libgobject-2.0.so.0
#29 0x00007ffff20e0ae2 in g_signal_emit () from /usr/lib64/libgobject-2.0.so.0
#30 0x00007ffff418aab2 in gtk_widget_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#31 0x00007ffff3fbad5b in gtk_box_forall () from /usr/lib64/libgtk-x11-2.0.so.0
#32 0x00007ffff4186d01 in gtk_widget_real_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#33 0x00007ffff20c76dc in _g_closure_invoke_va () from /usr/lib64/libgobject-2.0.so.0
#34 0x00007ffff20dffe1 in g_signal_emit_valist () from /usr/lib64/libgobject-2.0.so.0
#35 0x00007ffff20e0ae2 in g_signal_emit () from /usr/lib64/libgobject-2.0.so.0
#36 0x00007ffff418aab2 in gtk_widget_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#37 0x00007ffff4186d01 in gtk_widget_real_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#38 0x00007ffff20c776a in _g_closure_invoke_va () from /usr/lib64/libgobject-2.0.so.0
#39 0x00007ffff20dffe1 in g_signal_emit_valist () from /usr/lib64/libgobject-2.0.so.0
#40 0x00007ffff20e0ae2 in g_signal_emit () from /usr/lib64/libgobject-2.0.so.0
#41 0x00007ffff418aab2 in gtk_widget_unrealize () from /usr/lib64/libgtk-x11-2.0.so.0
#42 0x00007ffff418d800 in gtk_widget_dispose () from /usr/lib64/libgtk-x11-2.0.so.0
#43 0x00007ffff20cd8a0 in g_object_run_dispose () from /usr/lib64/libgobject-2.0.so.0
#44 0x00007ffff520af19 in Gtk::Dialog::~Dialog() () from /usr/lib64/libgtkmm-2.4.so.1
#45 0x00000000006faacd in DiagramSizeForm::~DiagramSizeForm (this=0x32174d0, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at diagram_size_form.cpp:17
#46 0x00000000006fabf9 in DiagramSizeForm::~DiagramSizeForm (this=0x32174d0, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at diagram_size_form.cpp:20
#47 0x00000000008d7191 in operator() (a0="X3\036\002\000\000\000\000\f\000\000\000\000\000\000\000X3\036\002", '\000' <repeats 12 times>"\210, , \003\000\000\000\000\f\000\000\000\000\000\000\000\006\000\000\000\000\000\000\000\017e\214\000\000\000\000\000\220A$\001\000\000\000\000\070\304\377\377\377\177\000\000\210, \003\000\000\000\000\071\215m\353\377\177\000\000\n\000\000\000\005\000\004\000\300\304\377\377\377\177\000\000\070A$\001\000\000\000\000\001\000\000\000\000\000\000\000\240\305\377\377\377\177\000\000 \311\377\377\377\177\000\000\060\210U\002\000\000\000\000-g\214", '\000' <repeats 13 times>, " \000\000\000\060\000\000\000\340\304\377\377\377\177\000\000\020\304\377\377\377\177\000\000\000\063\r\001\000\000\000\000\260\"\r\001\000\000\000\000\374\304\377\377\377\177\000\000\000\000\000\000\000\000\000\000x\231\036\003\000\000\000\000\210, \003\000\000\000\000\030(\t\001\000\000\000\000p"...<Address 0x7ffffffff000 out of bounds>, this=0x21ffb40) at /usr/include/boost/function/function_template.hpp:1013
#48 operator()<boost::function<void(std::basic_string<char>)>, boost::_bi::list0> (f=..., this=0x21ffb60, a=...) at /usr/include/boost/bind/bind.hpp:253
#49 operator() (this=0x21ffb40) at /usr/include/boost/bind/bind_template.hpp:20
#50 boost::detail::function::void_function_obj_invoker0<boost::_bi::bind_t<boost::_bi::unspecified, boost::function<void (std::string)>, boost::_bi::list1<boost::_bi::value<std::string> > >, void>::invoke(boost::detail::function::function_buffer&) (function_obj_ptr=...) at /usr/include/boost/function/function_template.hpp:153
#51 0x00000000008c650f in operator() (this=<optimized out>) at /usr/include/boost/function/function_template.hpp:1013
#52 wb::CommandUI::execute_builtin_command (this=0x1244138, name="diagram_size") at workbench/wb_command_ui.cpp:995
#53 0x00000000008c672d in wb::CommandUI::activate_command (this=0x1244138, command="builtin:diagram_size") at workbench/wb_command_ui.cpp:1065
#54 0x00000000008d70e5 in operator() (a0="\230\254Y\002", '\000' <repeats 12 times>"\230, \254Y\002\000\000\000\000\001", '\000' <repeats 15 times>"\340, \200U\002\000\000\000\000\340\200U\002\000\000\000\000\275\241k\000\000\000\000\000 \340\r\001\000\000\000\000\200\210U\002\000\000\000\000\200\210U\002\000\000\000\000\020)*\001\000\000\000\000p[\f\362\377\177\000\000\060L\376\001\000\000\000\000\200\210U\002\000\000\000\000\350\307\377\377\377\177\000\000\340\200U\002\000\000\000\000\200\210U\002\000\000\000\000\240\305\377\377\377\177\000\000\340\200U\002\000\000\000\000\200\210U\002\000\000\000\000\200\210U\002\000\000\000\000\240\305\377\377\377\177\000\000\200\210U\002\000\000\000\000\360:U\002\000\000\000\000\360\210U\002\000\000\000\000\366\002\000\000\000\000 \310\377\377\377\177\000\000\340\200U\002\000\000\000\000\003J\375\360\377\177\000\000\000\000\000@\000\000\000\000 \310\377\377\377\177\000\000\000\070\367\002\000\000\000\000\005\306\f\362\377\177\000\000`;)\001\000\000\000\000\320"...<Address 0x7ffffffff000 out of bounds>, this=0x254ea00) at /usr/include/boost/function/function_template.hpp:1013
#55 operator()<boost::function<void(std::basic_string<char>)>, boost::_bi::list0> (f=..., this=0x254ea20, a=...) at /usr/include/boost/bind/bind.hpp:253
#56 operator() (this=0x254ea00) at /usr/include/boost/bind/bind_template.hpp:20
#57 boost::detail::function::void_function_obj_invoker0<boost::_bi::bind_t<boost::_bi::unspecified, boost::function<void (std::string)>, boost::_bi::list1<boost::_bi::value<grt::Ref<grt::internal::String> > > >, void>::invoke(boost::detail::function::function_buffer&) (function_obj_ptr=...) at /usr/include/boost/function/function_template.hpp:153
#58 0x00000000006ba1bd in operator() (this=<optimized out>) at /usr/include/boost/function/function_template.hpp:1013
#59 m_invoke (connectionBody=..., this=<optimized out>) at /usr/include/boost/signals2/detail/signal_template.hpp:360
#60 operator() (connectionBody=..., this=<optimized out>) at /usr/include/boost/signals2/detail/signal_template.hpp:345
#61 dereference (this=<synthetic pointer>) at /usr/include/boost/signals2/detail/slot_call_iterator.hpp:82
#62 dereference<boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::signal0_impl<void, boost::signals2::optional_last_value<void>, int, std::less<int>, boost::function<void()>, boost::function<void(const boost::signals2::connection&)>, boost::signals2::mutex>::slot_invoker, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot0<void, boost::function<void()> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot0<void, boost::function<void()> >, boost::signals2::mutex> > > (f=<synthetic pointer>) at /usr/include/boost/iterator/iterator_facade.hpp:517
#63 operator* (this=<synthetic pointer>) at /usr/include/boost/iterator/iterator_facade.hpp:643
#64 operator()<boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::signal0_impl<void, boost::signals2::optional_last_value<void>, int, std::less<int>, boost::function<void()>, boost::function<void(const boost::signals2::connection&)>, boost::signals2::mutex>::slot_invoker, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot0<void, boost::function<void()> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot0<void, boost::function<void()> >, boost::signals2::mutex> > > (first=..., this=<optimized out>, last=...) at /usr/include/boost/signals2/optional_last_value.hpp:55
#65 operator()<boost::signals2::optional_last_value<void>, boost::signals2::detail::slot_call_iterator_t<boost::signals2::detail::signal0_impl<void, boost::signals2::optional_last_value<void>, int, std::less<int>, boost::function<void()>, boost::function<void(const boost::signals2::connection&)>, boost::signals2::mutex>::slot_invoker, std::_List_iterator<boost::shared_ptr<boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot0<void, boost::function<void()> >, boost::signals2::mutex> > >, boost::signals2::detail::connection_body<std::pair<boost::signals2::detail::slot_meta_group, boost::optional<int> >, boost::signals2::slot0<void, boost::function<void()> >, boost::signals2::mutex> > > (first=..., this=<optimized out>, combiner=..., last=...) at /usr/include/boost/signals2/detail/result_type_wrapper.hpp:64
#66 boost::signals2::detail::signal0_impl<void, boost::signals2::optional_last_value<void>, int, std::less<int>, boost::function<void ()>, boost::function<void (boost::signals2::connection const&)>, boost::signals2::mutex>::operator()() (this=0x2558830) at /usr/include/boost/signals2/detail/signal_template.hpp:246
#67 0x00007ffff7b1e3b5 in process_click (mi=0x2558930, item=0x2558760) at gtk/src/lf_menubar.cpp:51
#68 0x00007ffff3d0fb48 in Glib::SignalProxyNormal::slot0_void_callback(_GObject*, void*) () from /usr/lib64/libglibmm-2.4.so.1
#69 0x00007ffff20c7542 in g_closure_invoke () from /usr/lib64/libgobject-2.0.so.0
#70 0x00007ffff20d887d in signal_emit_unlocked_R () from /usr/lib64/libgobject-2.0.so.0
#71 0x00007ffff20e0939 in g_signal_emit_valist () from /usr/lib64/libgobject-2.0.so.0
#72 0x00007ffff20e0ae2 in g_signal_emit () from /usr/lib64/libgobject-2.0.so.0
#73 0x00007ffff418502e in gtk_widget_activate () from /usr/lib64/libgtk-x11-2.0.so.0
#74 0x00007ffff40808ad in gtk_menu_shell_activate_item () from /usr/lib64/libgtk-x11-2.0.so.0
#75 0x00007ffff4080c45 in gtk_menu_shell_button_release () from /usr/lib64/libgtk-x11-2.0.so.0
#76 0x00007ffff406d3d8 in _gtk_marshal_BOOLEAN__BOXED () from /usr/lib64/libgtk-x11-2.0.so.0
#77 0x00007ffff20c7542 in g_closure_invoke () from /usr/lib64/libgobject-2.0.so.0
#78 0x00007ffff20d8bd9 in signal_emit_unlocked_R () from /usr/lib64/libgobject-2.0.so.0
#79 0x00007ffff20e061e in g_signal_emit_valist () from /usr/lib64/libgobject-2.0.so.0
#80 0x00007ffff20e0ae2 in g_signal_emit () from /usr/lib64/libgobject-2.0.so.0
#81 0x00007ffff4185e31 in gtk_widget_event_internal () from /usr/lib64/libgtk-x11-2.0.so.0
#82 0x00007ffff406b563 in gtk_propagate_event () from /usr/lib64/libgtk-x11-2.0.so.0
#83 0x00007ffff406b8c3 in gtk_main_do_event () from /usr/lib64/libgtk-x11-2.0.so.0
#84 0x00007ffff363e5ec in gdk_event_dispatch () from /usr/lib64/libgdk-x11-2.0.so.0
#85 0x00007ffff0fe494a in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#86 0x00007ffff0fe4d10 in g_main_context_iterate.isra.23 () from /usr/lib64/libglib-2.0.so.0
#87 0x00007ffff0fe510a in g_main_loop_run () from /usr/lib64/libglib-2.0.so.0
#88 0x00007ffff406a917 in gtk_main () from /usr/lib64/libgtk-x11-2.0.so.0
#89 0x000000000069dcad in main (argc=1, argv=0x7fffffffd858) at main.cpp:311