Comment 2 for bug 1554219

StacktraceTop:
 g_type_check_instance_is_a () from /tmp/apport_sandbox_8IagQW/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 ido_calendar_menu_item_key_press (widget=widget@entry=0xbd3d00, event=0x20494c0, data=0xc247e0) at idocalendarmenuitem.c:159
 _gtk_marshal_BOOLEAN__BOXED (closure=0x148f590, return_value=0x7ffc09f19cd0, n_param_values=<optimized out>, param_values=0x7ffc09f19d30, invocation_hint=<optimized out>, marshal_data=<optimized out>) at /build/gtk+3.0-qjgeoX/gtk+3.0-3.18.8/./gtk/gtkmarshalers.c:86
 g_closure_invoke () from /tmp/apport_sandbox_8IagQW/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
 signal_emit_unlocked_R () from /tmp/apport_sandbox_8IagQW/usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0