Touchpad horizonal scroll gesture broken on GNOME 49

[KuxaBeast]

Describe the bug
Since the last update to GNOME 49 (and the compatible PaperWM release), I am unable to use the 3-finger horizontal scroll touchpad gesture. Vertical 3-finger scroll is not affected.

To Reproduce
Steps to reproduce the behavior:

1. Use the 3-finger horizontal touchpad gesture
2. The windows don't scroll horizontally, sometimes just for a split-second but overall unusable

Expected behavior
The windows move horizontally just as on GNOME 48.

System information:

Distribution: openSUSE Tumbleweed
GNOME Shell: 49.0
Display server: Wayland
PaperWM version: 49.0.0
Enabled extensions:
- caffeine@patapon.info
- steal-my-focus-window@steal-my-focus-window
- paperwm@paperwm.github.com
- Vitals@CoreCoding.com
- status-icons@gnome-shell-extensions.gcampax.github.com

Additional context
I figured out that if I patch the /usr/lib64/gnome-shell/libshell-17.so as described by this comment, the issue disappears and I can scroll normally again.

Hence I suspect some changes in gesture handling in GNOME 49 have been made and the workarounds in PaperWM will need to be amended accordingly, if possible.

[Fringale]

On my system (Aeon Desktop), whether or not this issue would appear after starting a session seemed decided by a coin flip. After some digging, I noticed that for me the difference comes down to this:

• If I go to the applications overview first thing after opening the session, before launching an application, then all is well and the issue does not occur.

• However, if the first application I launch is started directly from the dash (or panel, when using dash-to-panel), without going to the applications overview first, then:

  • The PaperWM three-finger horizontal swipe is broken
  • I get these errors in journalctl when swiping

gnome-shell[2197]: JS ERROR: TypeError: can't access property "children", this._pages[pageIndex] is undefined
getItemsAtPage@resource:///org/gnome/shell/ui/iconGrid.js:922:17
getItemsAtPage@resource:///org/gnome/shell/ui/iconGrid.js:1440:30
_translatePreviousPageIcons@resource:///org/gnome/shell/ui/appDisplay.js:314:34
_syncPageIndicators@resource:///org/gnome/shell/ui/appDisplay.js:387:14
goToPage@resource:///org/gnome/shell/ui/appDisplay.js:436:14
goToPage@resource:///org/gnome/shell/ui/appDisplay.js:1250:29
goToPage@resource:///org/gnome/shell/ui/appDisplay.js:1588:15
onComplete@resource:///org/gnome/shell/ui/appDisplay.js:731:36
_makeEaseCallback/<@resource:///org/gnome/shell/ui/environment.js:68:13
_easeActorProperty@resource:///org/gnome/shell/ui/environment.js:225:17
St.Adjustment.prototype.ease@resource:///org/gnome/shell/ui/environment.js:311:23
_swipeEnd@resource:///org/gnome/shell/ui/appDisplay.js:728:20
_endGesture@resource:///org/gnome/shell/ui/swipeTracker.js:651:14
_endTouchpadGesture@resource:///org/gnome/shell/ui/swipeTracker.js:672:14
_handleEvent@resource:///org/gnome/shell/ui/swipeTracker.js:196:18
@resource:///org/gnome/shell/ui/init.js:21:20

• And weirdly, the applications overview is empty (no application shown in the grid, only in the dash)

System information:

Distribution: Aeon
GNOME Shell: 49.0
Display server: Wayland
PaperWM version: 49.0.0
Enabled extensions:
- paperwm@paperwm.github.com

Would be interesting to know if those affected by the issue confirm this first application behaviour, and if they are openSUSE users like the reporter and me.

[cg505]

Probably related: https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2853
In particular, https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/ca80a3cd5d0c6b20ff55b4dc8b1c345aed8a3263.
This is pretty speculative, but it may be something like:

• without paperwm, the workspace SwipeTracker is enabled and captures swipe events on the desktop, and does not propagate them
• with paperwm, this SwipeTracker now has enabled=false, and so the swipe event is propagated down to the AppDisplay SwipeTracker, which can't handle it correctly since the app display view is not actually open
• before https://gitlab.gnome.org/GNOME/gnome-shell/-/commit/ca80a3cd5d0c6b20ff55b4dc8b1c345aed8a3263, this swipe event was filtered, but now it's not, causing a crash

Only took a cursory look so this could be wrong, but hopefully it's a starting point. Not sure what the appropriate fix would be.

[Fringale]

Great find @cg505!

I confirm that on my side the issue trigger boils down to the applications overview not having been opened prior to making a three-finger horizontal swipe on the desktop (with or without applications already opened).

[Vortex375]

I am on Arch Linux and I am always affected by this bug. But somehow my Gnome always starts into app overview directly after logging in. Then, it doesn't matter how I launch the first application, I am always affected by the issue. I have the Dash to Dock extension installed, if that's relevant.

This is the error that I am getting (same as seen previously):

gnome-shell[53386]: JS ERROR: TypeError: can't access property "children", this._pages[pageIndex] is undefined
    getItemsAtPage@resource:///org/gnome/shell/ui/iconGrid.js:922:17
    getItemsAtPage@resource:///org/gnome/shell/ui/iconGrid.js:1440:30
    _translatePreviousPageIcons@resource:///org/gnome/shell/ui/appDisplay.js:314:34
    _syncPageIndicators@resource:///org/gnome/shell/ui/appDisplay.js:387:14
    goToPage@resource:///org/gnome/shell/ui/appDisplay.js:436:14
    goToPage@resource:///org/gnome/shell/ui/appDisplay.js:1250:29
    goToPage@resource:///org/gnome/shell/ui/appDisplay.js:1588:15
    onComplete@resource:///org/gnome/shell/ui/appDisplay.js:731:36
    _makeEaseCallback/<@resource:///org/gnome/shell/ui/environment.js:68:13
    _easeActorProperty@resource:///org/gnome/shell/ui/environment.js:225:17
    St.Adjustment.prototype.ease@resource:///org/gnome/shell/ui/environment.js:311:23
    _swipeEnd@resource:///org/gnome/shell/ui/appDisplay.js:728:20
    _endGesture@resource:///org/gnome/shell/ui/swipeTracker.js:651:14
    _endTouchpadGesture@resource:///org/gnome/shell/ui/swipeTracker.js:672:14
    _handleEvent@resource:///org/gnome/shell/ui/swipeTracker.js:196:18
    @resource:///org/gnome/shell/ui/init.js:21:20

Software Information:

• OS Name: Arch Linux
• OS Build: (null)
• OS Type: 64-bit
• GNOME Version: 49
• Windowing System: Wayland
• Kernel Version: Linux 6.17.1-arch1-1

[cg505]

I confirm that on my side the issue trigger boils down to the applications overview not having been opened prior to making a three-finger horizontal swipe on the desktop (with or without applications already opened).

I cannot reproduce this.

I am on Arch Linux and I am always affected by this bug. But somehow my Gnome always starts into app overview directly after logging in. Then, it doesn't matter how I launch the first application, I am always affected by the issue. I have the Dash to Dock extension installed, if that's relevant.

This is the same for me. I am also on Arch.

[Fringale]

Just to be sure, here are the detailed steps that I do as a workaround (with all extensions disabled except PaperWM):

1. Log into Gnome session: it displays the Activities overview by default
   

2. Click on the application grid button in the Dash or Super+A to get to the Applications overview
   

3. Then whatever I do, the three-finger horizontal swipe will work as expected for the remainder of the session.

@cg505 @Vortex375 This does not work on your side?

---

And on the contrary to reproduce the issue 100%, I do the following:

1. Log into Gnome session (it displays the Activities overview by default)

2. Click to get to the desktop and do a three-finger horizontal swipe there
   

3. Swipe up twice or press Super twice or press Super+A to get to the Applications overview: the Applications overview is empty (no applications shown in the grid), and the three-finger horizontal swipe will be broken and generate journalctl errors as shown in above comments.
   

[LBY-L]

Fedora 43, exact same issue as well.

[ecelia]

I confirm this issue with Fedora 43.

[michalmielczynski]

confirming that on Fedora 43, Wayland, Thinkpad X1