Thunderbird fails to print duplex

[Wolf Rogner]

Thunderbird does not print duplex even when set to do so.

Printer settings, about:config is ignored.

Resetting about:configs print.print_duplex restores a string value. When setting it, an integer is set. This is the same behaviour that firefox exposes.

Did not happen before the change to the new engine.

Behaviour can only be observed on Linux (not on Mac).

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: thunderbird 1:60.2.1+build1-0ubuntu1
ProcVersionSignature: Ubuntu 4.18.0-11.12-generic 4.18.12
Uname: Linux 4.18.0-11-generic x86_64
AddonCompatCheckDisabled: False
ApportVersion: 2.20.10-0ubuntu13.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: wolf 14366 F.... pulseaudio
 /dev/snd/controlC1: wolf 14366 F.... pulseaudio
BuildID: 20181011091051
Channel: Unavailable
CurrentDesktop: ubuntu:GNOME
Date: Wed Nov 21 06:52:45 2018
Extensions: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
InstallationDate: Installed on 2018-04-30 (204 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
IpRoute:
 default via 10.201.255.254 dev wlp3s0 proto dhcp metric 600
 10.201.0.0/16 dev wlp3s0 proto kernel scope link src 10.201.41.123 metric 600
 169.254.0.0/16 dev wlp3s0 scope link metric 1000
Locales: extensions.sqlite corrupt or missing
PrefSources: prefs.js
Profiles: Profile0 (Default) - LastVersion=60.2.1/20181011091051 (In use)
RunningIncompatibleAddons: False
SourcePackage: thunderbird
Themes: extensions.sqlite corrupt or missing
UpgradeStatus: Upgraded to cosmic on 2018-10-20 (31 days ago)
dmi.bios.date: 08/08/2017
dmi.bios.vendor: Apple Inc.
dmi.bios.version: MBP121.88Z.0171.B00.1708080033
dmi.board.name: Mac-E43C1C25D4880AD6
dmi.board.vendor: Apple Inc.
dmi.board.version: MacBookPro12,1
dmi.chassis.type: 9
dmi.chassis.vendor: Apple Inc.
dmi.chassis.version: Mac-E43C1C25D4880AD6
dmi.modalias: dmi:bvnAppleInc.:bvrMBP121.88Z.0171.B00.1708080033:bd08/08/2017:svnAppleInc.:pnMacBookPro12,1:pvr1.0:rvnAppleInc.:rnMac-E43C1C25D4880AD6:rvrMacBookPro12,1:cvnAppleInc.:ct9:cvrMac-E43C1C25D4880AD6:
dmi.product.family: MacBook Pro
dmi.product.name: MacBookPro12,1
dmi.product.version: 1.0
dmi.sys.vendor: Apple Inc.