With client side decoration, Firefox preempts any middle click on title bar

[Franck]

Since recent versions, Firefox uses client-side decoration to draw its title bar.
I have a mouse shortcut defined in gnome-tweaks that allows me to minimize windows on middle mouse button click on title bar
This works well, except on new Firefox, where it will open a new tab...

I didn't find the way to disable this behaviour.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: firefox 66.0.3+build1-0ubuntu1
ProcVersionSignature: Ubuntu 5.0.0-8.9-generic 5.0.1
Uname: Linux 5.0.0-8-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
AddonCompatCheckDisabled: False
ApportVersion: 2.20.10-0ubuntu26
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: franck 3795 F.... pulseaudio
 /dev/snd/pcmC1D0c: franck 3795 F...m pulseaudio
 /dev/snd/controlC0: franck 3795 F.... pulseaudio
 /dev/snd/pcmC0D7p: franck 3795 F...m pulseaudio
BuildID: 20190410124846
Channel: Unavailable
CurrentDesktop: GNOME
Date: Thu Apr 11 20:28:43 2019
EcryptfsInUse: Yes
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)
IpRoute:
 default via 10.0.0.1 dev enp0s25 proto dhcp metric 100
 default via 10.0.0.1 dev wlp3s0 proto dhcp metric 600
 10.0.0.0/24 dev enp0s25 proto kernel scope link src 10.0.0.14 metric 100
 10.0.0.0/24 dev wlp3s0 proto kernel scope link src 10.0.0.246 metric 600
 10.204.48.0/24 dev lxdbr0 proto kernel scope link src 10.204.48.1
Locales: extensions.sqlite corrupt or missing
PrefSources: prefs.js
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fr_FR.UTF-8
 SHELL=/bin/bash
Profiles: Profile0 (Default) - LastVersion=66.0.3/20190410124846 (In use)
RunningIncompatibleAddons: False
SourcePackage: firefox
Themes: extensions.sqlite corrupt or missing
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/27/2017
dmi.bios.vendor: LENOVO
dmi.bios.version: G7ETA9WW (2.69 )
dmi.board.asset.tag: Not Available
dmi.board.name: 2353CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG7ETA9WW(2.69):bd09/27/2017:svnLENOVO:pn2353CTO:pvrThinkPadT430s:rvnLENOVO:rn2353CTO:rvrNotDefined:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.family: ThinkPad T430s
dmi.product.name: 2353CTO
dmi.product.sku: LENOVO_MT_2353
dmi.product.version: ThinkPad T430s
dmi.sys.vendor: LENOVO

[Olivier Tilloy (osomon)]

Thanks for the report Franck.
This sounds like it might be an upstream bug. Would you mind filing it at https://bugzilla.mozilla.org/enter_bug.cgi#h=dupes%7CFirefox, and sharing the link to it here? Thanks!

[Franck (alci)]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

On Linux (Gnome), Firefox now use client side decoration. Since this is the case, my workflow is broken: in Gnome, I have configured middle mouse on title bars to behave as minimize the window.

It used to work when FF didn't use CSD. It works in other apps.

But with CSD, FF now opens a new tab instead of letting the WM minimize the window.

Actual results:

middle mouse click in title bar always results in opening a new tab

Expected results:

"open a new tab on middle click in title bar" should be an option in about:config (true by default) and let the wm do its job if false

[Franck (alci)]

I opened a bug upstream: https://bugzilla.mozilla.org/show_bug.cgi?id=1567176

[Olivier Tilloy (osomon)]

Thanks!

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.