Public bug reported: # Summary On Ubuntu 25.10 with GNOME Shell 49 / Mutter 49 in a Wayland session, the "dynamic workspaces" behavior intermittently breaks: Mutter stops creating the trailing empty workspace that should always sit at the end of the workspace stack. Once in this state, adding windows to the highest existing workspace does not cause a new empty workspace to appear, so the user is effectively capped at the current workspace count. The only known recovery is to log out and log back in.
# Environment - OS: Ubuntu 25.10 - Session: Wayland (XDG_SESSION_TYPE=wayland), GNOME on Wayland - Packages: - mutter-common 49.0-2ubuntu5 - libmutter-17-0 49.0-2ubuntu5 - gnome-shell 49.0-1ubuntu1 - gnome-shell-common 49.0-1ubuntu1 - Hardware: Dell XPS 13 (9320), single internal display (eDP-1, 3456x2160) - Relevant dconf at time of failure: - org.gnome.mutter dynamic-workspaces = true - org.gnome.mutter workspaces-only-on-primary = false - org.gnome.mutter experimental-features = ['x11-randr-fractional-scaling'] - org.gnome.desktop.wm.preferences num-workspaces = 4 (default; not in effect because dynamic is on) # Expected behavior With dynamic-workspaces=true, Mutter should maintain `(occupied workspaces) + 1 trailing empty` workspace at all times. Placing a window onto the currently-empty trailing workspace should immediately cause a new empty trailing workspace to appear. # Actual behavior After some unpredictable amount of session uptime, the trailing empty workspace stops being created. With windows already on workspaces 1..N: 1. The overview shows exactly N workspace strips (no empty N+1). 2. Dragging a window from workspace 1 onto workspace N (or any existing workspace) does not spawn a new empty workspace N+1. 3. The user is effectively unable to create additional workspaces. The bug appears stochastically — it recurs frequently but no deterministic trigger has been identified. Once stuck, the broken state is fully reproducible: every drag onto the highest workspace fails to grow the stack. # Steps to reproduce A deterministic trigger has not been isolated. Once in the broken state, the following reliably reproduces the failed growth: 1. Confirm `gsettings get org.gnome.mutter dynamic-workspaces` returns `true`. 2. Open the Activities overview; observe N workspace strips matching the number of occupied workspaces (no extra trailing empty). 3. Drag a window onto workspace N (the highest existing one) and release. 4. Observe that no workspace N+1 is created. # What has been ruled out - **dconf misconfiguration**: dynamic-workspaces is `true` throughout; toggling it off and back on (`gsettings set org.gnome.mutter dynamic-workspaces false; gsettings set org.gnome.mutter dynamic-workspaces true`) does not clear the stuck state, even after resetting num-workspaces to its default. - **Third-party extensions**: bug persists with `[email protected]` and `[email protected]` both disabled. Other enabled extensions are stock Ubuntu/GNOME (ubuntu-dock, ubuntu-appindicators, ding, snapd-prompting, display-brightness-ddcutil). - **Multi-monitor / workspaces-only-on-primary edge cases**: single monitor, workspaces-only-on-primary=false. - **Stale fixed-mode config**: num-workspaces was reset to default 4 with no effect. # Workaround `gnome-session-quit --logout --no-prompt` followed by logging back in restores correct dynamic-workspaces behavior immediately. Mutter cannot be restarted in place on Wayland, so no lighter-weight recovery is known. # Additional info I have a local diagnostic script that captures dconf state, extension list, journal warnings, kernel GPU/DRM events, suspend/resume history, and gnome-shell process info when the bug is active. I will attach its output the next time the bug occurs. Happy to gather any other targeted data (specific journal filters, mutter debug flags, etc.) if a triager can point me at what would be most useful. ProblemType: Bug DistroRelease: Ubuntu 25.10 Package: mutter (not installed) ProcVersionSignature: Ubuntu 6.17.0-29.29-generic 6.17.13 Uname: Linux 6.17.0-29-generic x86_64 ApportVersion: 2.33.1-0ubuntu3 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Thu May 28 10:53:40 2026 InstallationDate: Installed on 2022-09-30 (1336 days ago) InstallationMedia: Ubuntu 22.04.1 LTS "Jammy Jellyfish" - Release amd64 (20220809.1) ProcEnviron: LANG=en_US.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=xterm-256color XDG_RUNTIME_DIR=<set> SourcePackage: mutter UpgradeStatus: Upgraded to questing on 2025-11-04 (206 days ago) ** Affects: mutter (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug questing wayland-session -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2154487 Title: mutter: dynamic-workspaces stops spawning the trailing empty workspace after some uptime (only logout clears it) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/2154487/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
