I installed workrave from source (commit 374ffa64628609d967a2deb92ae117e1ad40b483) on my arch linux machine. I built it with configure; make; make install.

Launching workrave from the console causes it to coredump. Here is the back trace from gdb

-------------------------------------------------
rogram terminated with signal SIGSEGV, Segmentation fault.
#0  0x0000000000000020 in ?? ()
[Current thread is 1 (Thread 0x7efd05e589c0 (LWP 1126))]
(gdb) bt
#0  0x0000000000000020 in  ()
#1  0x00007efd03e8156b in XQueryExtension () at /usr/lib/libX11.so.6
#2  0x00007efd03e750f2 in XInitExtension () at /usr/lib/libX11.so.6
#3  0x00007efcfee5938f in XextAddDisplay () at /usr/lib/libXext.so.6
#4  0x00007efd050ed061 in XScreenSaverQueryExtension () at /usr/lib/libXss.so.1
#5  0x00000000004cbc38 in XScreenSaverMonitor::init() (this=0x1856290) at XScreenSaverMonitor.cc:71
#6  0x00000000004caddc in UnixInputMonitorFactory::get_monitor(IInputMonitorFactory::MonitorCapability) (this=0x1856190, capability=<optimized out>) at UnixInputMonitorFactory.cc:107
#7  0x00000000004cc1bc in ActivityMonitor::ActivityMonitor() (this=0x18561f0) at ActivityMonitor.cc:76
#8  0x00000000004aaf06 in Core::init_monitor(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (this=0x1849bf0, display_name=...) at Core.cc:286
#9  0x00000000004ad37a in Core::init(int, char**, workrave::IApp*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (this=0x1849bf0, argc=<optimized out>, argv=<optimized out>, app=<optimized out>, display_name="wayland-0") at Core.cc:171
#10 0x000000000046a253 in GUI::init_core() (this=this@entry=0x17798a0) at GUI.cc:544
#11 0x000000000045e508 in GUI::main() (this=this@entry=0x17798a0) at GUI.cc:221
#12 0x000000000048c26b in run(int, char**) (argc=1, argv=0x7ffe3c1759a8) at main.cc:68
#13 0x00007efcff487291 in __libc_start_main () at /usr/lib/libc.so.6
#14 0x000000000046054a in _start ()

---------------------------------------------------

Any chance you are running Gnome on Wayland?

Yes I am running Gnome on Wayland

Workrave currently does not support Wayland. I'm trying to add Wayland support to Workrave.

I noticed that in Arch you can select 'GNOME on Xorg' in the login screen. Workrave will run in the mode.

*** Bug 1255 has been marked as a duplicate of this bug. ***

Is there any plans to port workrave to GTK 3?
I think that will fix several issues including this one.

Hi I just tried 1.10.18 and it crashes on Wayland on ArchLinux. Here is the info the core dump:
           PID: 22013 (workrave)
           UID: 1000 (amir)
           GID: 1000 (amir)
        Signal: 5 (TRAP)
     Timestamp: Wed 2017-10-25 16:07:34 CEST (4min 14s ago)
  Command Line: workrave
    Executable: /usr/bin/workrave
 Control Group: /u**@10**.service/gnome-terminal-server.service
          Unit: us**@10**.service
     User Unit: gnome-terminal-server.service
         Slice: user-1000.slice
     Owner UID: 1000 (amir)
       Boot ID: 8b34de00a92d4b7a9886ddd156da6c56
    Machine ID: 7976738470854f418d246faebfc5aea5
      Hostname: archie
       Storage: /var/lib/systemd/coredump/core.workrave.1000.8b34de00a92d4b7a9886ddd156da6c56.22013.1508940454000000.lz4
       Message: Process 22013 (workrave) of user 1000 dumped core.
                
                Stack trace of thread 22013:
                #0  0x00007fafeb3d5cd2 n/a (libglib-2.0.so.0)
                #1  0x00007fafeb3d5ecd g_log_default_handler (libglib-2.0.so.0)
                #2  0x00007fafeb3d64ef g_logv (libglib-2.0.so.0)
                #3  0x00007fafeb3d6680 g_log (libglib-2.0.so.0)
                #4  0x00007fafec35fd72 n/a (libgio-2.0.so.0)
                #5  0x00007fafec2a47e1 g_settings_get_value (libgio-2.0.so.0)
                #6  0x0000564c6c59ae52 _ZNK21GSettingsConfigurator9get_valueERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE11VariantTypeR7Variant (workrave)
                #7  0x0000564c6c5960aa _ZNK12Configurator9get_valueERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE11VariantTypeR7Variant (workrave)
                #8  0x0000564c6c597503 _ZN12Configurator9set_valueERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEER7VariantN8workrave11ConfigFlagsE (workrave)
                #9  0x0000564c6c5980e9 _ZN12Configurator9set_valueERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEiN8workrave11ConfigFlagsE (workrave)
                #10 0x0000564c6c56eac3 _ZN4Core12init_monitorERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE (workrave)
                #11 0x0000564c6c57136c _ZN4Core4initEiPPcPN8workrave4IAppERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE (workrave)
                #12 0x0000564c6c526e8c _ZN3GUI9init_coreEv (workrave)
                #13 0x0000564c6c5187b6 _ZN3GUI4mainEv (workrave)
                #14 0x0000564c6c54dbfe run (workrave)
                #15 0x00007fafea4c1f6a __libc_start_main (libc.so.6)
                #16 0x0000564c6c51aa4a _start (workrave)
                
                Stack trace of thread 22016:
                #0  0x00007fafea591c49 syscall (libc.so.6)
                #1  0x00007fafeb3f45dd n/a (libglib-2.0.so.0)
                #2  0x00007fafec327274 n/a (libgio-2.0.so.0)
                #3  0x00007fafec2b4a60 n/a (libgio-2.0.so.0)
                #4  0x00007fafec3470dc n/a (libgio-2.0.so.0)
                #5  0x00007fafec347119 n/a (libgio-2.0.so.0)
                #6  0x00007fafeb3cb0be g_main_context_dispatch (libglib-2.0.so.0)
                #7  0x00007fafeb3ccf69 n/a (libglib-2.0.so.0)
                #8  0x00007fafeb3cdf42 g_main_loop_run (libglib-2.0.so.0)
                #9  0x00007fafec2a7e28 n/a (libgio-2.0.so.0)
                #10 0x00007fafeb3c11eb n/a (libglib-2.0.so.0)
                #11 0x00007fafea85f08a start_thread (libpthread.so.0)
                #12 0x00007fafea59724f __clone (libc.so.6)
                
                Stack trace of thread 22014:
                #0  0x00007fafeb3a4b29 g_datalist_id_set_data_full (libglib-2.0.so.0)
                #1  0x00007fafeb69d26c n/a (libgobject-2.0.so.0)
                #2  0x00007fafeb69d407 n/a (libgobject-2.0.so.0)
                #3  0x00007fafeb6ab818 g_type_create_instance (libgobject-2.0.so.0)
                #4  0x00007fafeb69f469 n/a (libgobject-2.0.so.0)
                #5  0x00007fafeb6a097d g_object_new_with_properties (libgobject-2.0.so.0)
                #6  0x00007fafeb6a0a7a g_object_new (libgobject-2.0.so.0)
                #7  0x00007fafec348647 g_task_new (libgio-2.0.so.0)
                #8  0x00007fafec327beb n/a (libgio-2.0.so.0)
                #9  0x00007fafec327dd7 g_dbus_connection_send_message_with_reply (libgio-2.0.so.0)
                #10 0x00007fafec32bbe6 n/a (libgio-2.0.so.0)
                #11 0x00007fafec32bd85 g_dbus_connection_call (libgio-2.0.so.0)
                #12 0x00007fafe0a249e0 n/a (libdconfsettings.so)
                #13 0x00007fafeb3cb0be g_main_context_dispatch (libglib-2.0.so.0)
                #14 0x00007fafeb3ccf69 n/a (libglib-2.0.so.0)
                #15 0x00007fafeb3ccfae g_main_context_iteration (libglib-2.0.so.0)
                #16 0x00007fafe0a24b0e n/a (libdconfsettings.so)
                #17 0x00007fafeb3c11eb n/a (libglib-2.0.so.0)
                #18 0x00007fafea85f08a start_thread (libpthread.so.0)
                #19 0x00007fafea59724f __clone (libc.so.6)
                
                Stack trace of thread 22015:
                #0  0x00007fafea58cd4b __poll (libc.so.6)
                #1  0x00007fafeb3cced3 n/a (libglib-2.0.so.0)
                #2  0x00007fafeb3ccfae g_main_context_iteration (libglib-2.0.so.0)
                #3  0x00007fafeb3cd002 n/a (libglib-2.0.so.0)
                #4  0x00007fafeb3c11eb n/a (libglib-2.0.so.0)
                #5  0x00007fafea85f08a start_thread (libpthread.so.0)
                #6  0x00007fafea59724f __clone (libc.so.6)


If you need more information, please let me know.

Sorry the issue I reported in my last comment does not just happen on Wayland. It happens on X11 too. Here is the error I get through the terminal:
 (workrave:25615): GLib-GIO-ERROR **: Settings schema 'org.workrave.monitor' does not contain a key named 'sensitivity'

And here is the gdb backtrace:
#0  0x00007f0cf6e0bcd2 in  () at /usr/lib/libglib-2.0.so.0
#1  0x00007f0cf6e0becd in g_log_default_handler () at /usr/lib/libglib-2.0.so.0
#2  0x00007f0cf6e0c4ef in g_logv () at /usr/lib/libglib-2.0.so.0
#3  0x00007f0cf6e0c680 in g_log () at /usr/lib/libglib-2.0.so.0
#4  0x00007f0cf7d95d72 in  () at /usr/lib/libgio-2.0.so.0
#5  0x00007f0cf7cda7e1 in g_settings_get_value () at /usr/lib/libgio-2.0.so.0
#6  0x0000564d71da5e52 in GSettingsConfigurator::get_value(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, VariantType, Variant&) const ()
#7  0x0000564d71da10aa in Configurator::get_value(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, VariantType, Variant&) const ()
#8  0x0000564d71da2503 in Configurator::set_value(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, Variant&, workrave::ConfigFlags) ()
#9  0x0000564d71da30e9 in Configurator::set_value(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, int, workrave::ConfigFlags) ()
#10 0x0000564d71d79ac3 in Core::init_monitor(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()
#11 0x0000564d71d7c36c in Core::init(int, char**, workrave::IApp*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) ()
#12 0x0000564d71d31e8c in GUI::init_core() ()
#13 0x0000564d71d237b6 in GUI::main() ()
#14 0x0000564d71d58bfe in run ()
#15 0x00007f0cf5ef7f6a in __libc_start_main () at /usr/lib/libc.so.6
#16 0x0000564d71d25a4a in _start ()

I am on X11 (not Wayland) and experience this same bug, it is not due to Wayland. I am on archlinux using i3 window manager.

Also, you may be interested in the issue page on the archlinux bug tracker:

https://bugs.archlinux.org/task/56115?project=5&cat%5B0%5D=33&string=workrave

They identified the commit that causes the crash as:

https://github.com/rcaelers/workrave/commit/81329192d052fc89b06d6783cd46c791c8e0d0b9