Bug#956297: [gnome] Gnome Shell crashes in Wayland if a window is "Stick" in all workspaces and a popup menu is open

[Sergio Costas]

Package: gnome
Version: 3.34.2
Severity: important
Tags: patch

--- Please enter the report below this line. ---

If a window is marked as "sticky" (this is, that it must be shown in all 
workspaces), showing a popup menu with a submenu makes gnome shell to 
crash. Tested on:

- Debian SID and Fedora 31, all of them with Gnome Shell 3.34.2: the bug 
is present.

- Ubuntu 19.04 with Gnome Shell 3.32: the bug is present (also there is 
a bug report in Ubuntu: 
https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1864326 )

- Debian Buster (current stable) with Gnome Shell 3.30.2: no bug there.

- Fedora 32 beta with Gnome Shell 3.36: no bug.

There is a one-line patch (already applied in Gnome Shell 3.36) that 
fixes this: https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1139

In the original bug-report that led to that MR it says to launch 
transmission-bittorrent, set the window as "show in all desktops", and 
open a menu. I've been unable to find that option, so I wrote a little 
gnome shell extension that allows to test it (download it from 
http://www.rastersoft.com/test_submenu_stick.zip ). Just install it, 
exit and enter again the Wayland gnome shell session, enable it, and a 
window will appear. Right click in the window to show the menu and go to 
the second option (the one with a submenu). Gnome shell will crash (but 
only in Wayland; in X11 it will work fine).


--- System information. ---

Architecture:
Kernel: Linux 5.4.0-4-amd64

Debian Release: bullseye/sid
500 unstable-debug debug.mirrors.debian.org
500 unstable ftp.debian.org
500 suldr www.bchemnet.com
500 stable repo.skype.com
500 stable linux.teamviewer.com
500 stable dl.google.com

--- Package information. ---
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