#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007fc20341b537 in __GI_abort () at abort.c:79
#2  0x00007fc20341b40f in __assert_fail_base
    (fmt=0x7fc203584128 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=0x5602e7283f31 "regions.size () == 1", file=0x5602e7283f10 "../gtk2_ardour/editor_regions.cc", line=1150, function=<optimized out>) at assert.c:92
#3  0x00007fc20342a662 in __GI___assert_fail
    (assertion=0x5602e7283f31 "regions.size () == 1", file=0x5602e7283f10 "../gtk2_ardour/editor_regions.cc", line=1150, function=0x5602e7283ec8 "boost::shared_ptr<ARDOUR::Region> EditorRegions::get_dragged_region()") at assert.c:101
#4  0x00005602e7b1c33a in EditorRegions::get_dragged_region() (this=0x5602ee77acb0) at ../gtk2_ardour/editor_regions.cc:1150
#5  0x00005602e7a580cd in Editor::track_canvas_drag_motion(Glib::RefPtr<Gdk::DragContext> const&, int, int, unsigned int) (this=0x5602ee4d60c0, context=..., x=860, y=194, time=209469444)
    at ../gtk2_ardour/editor_canvas_events.cc:1204
#6  0x00005602e7a54303 in sigc::bound_mem_functor4<bool, Editor, Glib::RefPtr<Gdk::DragContext> const&, int, int, unsigned int>::operator()(Glib::RefPtr<Gdk::DragContext> const&, int const&, int const&, unsigned int const&) const (this=0x5602e9425dc8, _A_a1=..., _A_a2=@0x7ffd7b7b4e4c: 860, _A_a3=@0x7ffd7b7b4e48: 194, _A_a4=@0x7ffd7b7b4e44: 209469444)
    at /usr/include/sigc++-2.0/sigc++/functors/mem_fun.h:2303
#7  0x00005602e7a53933 in sigc::adaptor_functor<sigc::bound_mem_functor4<bool, Editor, Glib::RefPtr<Gdk::DragContext> const&, int, int, unsigned int> >::operator()<Glib::RefPtr<Gdk::DragContext> const&, int const&, int const&, unsigned int const&>(Glib::RefPtr<Gdk::DragContext> const&, int const&, int const&, unsigned int const&) const
    (this=0x5602e9425dc0, _A_arg1=..., _A_arg2=@0x7ffd7b7b4e4c: 860, _A_arg3=@0x7ffd7b7b4e48: 194, _A_arg4=@0x7ffd7b7b4e44: 209469444)
    at /usr/include/sigc++-2.0/sigc++/adaptors/adaptor_trait.h:149
#8  0x00005602e7a52ce0 in sigc::internal::slot_call4<sigc::bound_mem_functor4<bool, Editor, Glib::RefPtr<Gdk::DragContext> const&, int, int, unsigned int>, bool, Glib::RefPtr<Gdk::DragContext> const&, int, int, unsigned int>::call_it(sigc::internal::slot_rep*, Glib::RefPtr<Gdk::DragContext> const&, int const&, int const&, unsigned int const&)
    (rep=0x5602e9425d90, a_1=..., a_2=@0x7ffd7b7b4e4c: 860, a_3=@0x7ffd7b7b4e48: 194, a_4=@0x7ffd7b7b4e44: 209469444) at /usr/include/sigc++-2.0/sigc++/functors/slot.h:284
#9  0x00007fc204249554 in  () at /lib/x86_64-linux-gnu/libgtkmm-2.4.so.1
#10 0x00007fc2047ba737 in  () at /lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#11 0x00007fc204c2d0a2 in g_closure_invoke () at /lib/x86_64-linux-gnu/libgobject-2.0.so.0
#12 0x00007fc204c3f602 in  () at /lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007fc204c45259 in g_signal_emit_valist () at /lib/x86_64-linux-gnu/libgobject-2.0.so.0
#14 0x00007fc204c45e5f in g_signal_emit_by_name () at /lib/x86_64-linux-gnu/libgobject-2.0.so.0
#15 0x00007fc2048f6f4a in  () at /lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#16 0x00007fc2048f6a21 in  () at /lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#17 0x00007fc2047b8de3 in gtk_main_do_event () at /lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#18 0x00007fc204624afc in  () at /lib/x86_64-linux-gnu/libgdk-x11-2.0.so.0
#19 0x00007fc204b39e6b in g_main_context_dispatch () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007fc204b3a118 in  () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007fc204b3a40b in g_main_loop_run () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007fc2047b7b2a in gtk_main () at /lib/x86_64-linux-gnu/libgtk-x11-2.0.so.0
#23 0x00007fc205062502 in Gtkmm2ext::UI::run(Receiver&) (this=0x5602e8d84d40, old_receiver=...) at ../libs/gtkmm2ext/gtk_ui.cc:310
#24 0x00005602e7df4b55 in main(int, char**) (argc=1, argv=0x7ffd7b7b5a78) at ../gtk2_ardour/main.cc:410