caribou won't start in GNOME Flashback

[Jeremy Bícha]

sudo apt install caribou-antler libcaribou-gtk3-module gnome-session-flashback

Open Settings > Universal Access and turn on the Screen Keyboard

Restart and log into GNOME Flashback.

The onscreen keyboard fails to start. journalctl shows this error:

Traceback (most recent call last):
  File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/usr/lib/python3/dist-packages/caribou/antler/main.py", line 71, in <module>
    command(args).run()
  File "/usr/lib/python3/dist-packages/caribou/antler/main.py", line 17, in __init__
    self.window = AntlerWindowEntry(AntlerKeyboardView)
  File "/usr/lib/python3/dist-packages/caribou/antler/window.py", line 413, in __init__
    AntlerWindow.__init__(self, keyboard_view_factory, placement)
  File "/usr/lib/python3/dist-packages/caribou/antler/window.py", line 225, in __init__
    self.keyboard_view = keyboard_view_factory (keyboard_type=settings.keyboard_type.value)
  File "/usr/lib/python3/dist-packages/caribou/antler/keyboard_view.py", line 233, in __init__
    [GLib.get_user_data_dir()] + list(GLib.get_system_data_dirs()))
  File "/usr/lib/python3/dist-packages/caribou/antler/keyboard_view.py", line 297, in _load_style
    provider.load_from_path(fn)
GLib.Error: gtk-css-provider-error-quark: style.css:16:8not a number (1)

ProblemType: Crash
DistroRelease: Ubuntu 18.04
Package: caribou 0.4.21-2
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
ApportVersion: 2.20.8-0ubuntu2
Architecture: amd64
CrashCounter: 1
CurrentDesktop: GNOME-Flashback:GNOME
Date: Wed Nov 29 15:15:12 2017
ExecutablePath: /usr/lib/caribou/caribou
InstallationDate: Installed on 2017-10-13 (47 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Beta amd64 (20171012)
ProcCmdline: /usr/lib/caribou/caribou
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Signal: 5
SourcePackage: caribou
StacktraceTop:
 ?? ()
 ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
 ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
Title: caribou crashed with signal 5
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

StacktraceTop:
 caribou_daemon_on_get_proxy_ready (obj=<optimized out>, res=0x55b39f0871a0, self=0x55b39f0a0220) at daemon.c:660
 _caribou_daemon_on_get_proxy_ready_gasync_ready_callback (source_object=<optimized out>, res=0x55b39f0871a0, self=0x55b39f0a0220) at daemon.c:1384
 g_task_return_now (task=0x55b39f0871a0) at ../../../../gio/gtask.c:1145
 g_task_return (task=0x55b39f0871a0, type=<optimized out>) at ../../../../gio/gtask.c:1203
 init_second_async_cb (source_object=<optimized out>, res=<optimized out>, user_data=0x55b39f0871a0) at ../../../../gio/gdbusproxy.c:1810

[Launchpad Janitor (janitor)]

This bug was fixed in the package caribou - 0.4.21-3

---------------
caribou (0.4.21-3) unstable; urgency=medium

  * Have caribou-antler depend on libcaribou-gtk-module and
    libcaribou-gtk3-module
  * Don't have libcaribou-gtk-module depend on GTK+ 2 to allow this
    module to be installed without forcing GTK+ 2 to be installed.
  * Bump debhelper compat to 10
  * Use debian/docs to install NEWS
  * Cherry-pick fix-font-property-in-style.css.patch:
    - Fix caribou-antler crash (LP: #1735298)

 -- Jeremy Bicha <email address hidden> Fri, 01 Dec 2017 15:29:48 -0500