Nautilus icon missing from taskbar (21.10; Xorg)

[Springnuts]

Upgraded to 21.10. I am using Ubuntu Tweaks to set a bottom of screen taskbar. Nautilus (Files) was pinned to the taskbar. I discovered that Waland was incompatible with my graphics card, so switched to Xorg. I think at this point the Files icon disappeared (and just possibly some others I have not noticed). I can launch Nautilus from the launcher, but the icon does not appear.
Nautilus version 1:40.2-1ubuntu1

Expected behaviour 1: The pinned icon would remain visible on the taskbar.
Observed behaviour 1: The pinned icon disappeared from the taskbar.

Expected behaviour 2: When Nautilus is open the icon will be visible on the taskbar.
Observed behaviour 2: When Nautilus is open the icon is not visible on the taskbar.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: nautilus 1:40.2-1ubuntu1
ProcVersionSignature: Ubuntu 5.13.0-20.20-generic 5.13.14
Uname: Linux 5.13.0-20-generic x86_64
ApportVersion: 2.20.11-0ubuntu70
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 24 21:28:18 2021
ExecutablePath: /usr/bin/nautilus
InstallationDate: Installed on 2021-05-27 (149 days ago)
InstallationMedia: Ubuntu 21.04 "Hirsute Hippo" - Release amd64 (20210420)
ProcEnviron:
 SHELL=/bin/bash
 XDG_RUNTIME_DIR=<set>
 PATH=(custom, no user)
 LANGUAGE=en_GB:en
 LANG=en_GB.UTF-8
SourcePackage: nautilus
UpgradeStatus: Upgraded to impish on 2021-10-14 (9 days ago)
usr_lib_nautilus:
 evince 40.4-2
 file-roller 3.40.0-2
 nautilus-dropbox 2019.02.14-1ubuntu1
 nautilus-extension-gnome-terminal 3.38.1-1ubuntu2
 nautilus-share 0.7.3-2ubuntu4

[Sebastien Bacher (seb128)]

Thank you for your bug report. Could you add a screenshot showing the issue as well as a 'journalctl -b 0' log?

[JEMYZHANG (jemy-zhang)]

journalctl errors show while opening nautilus:

```
11月 06 10:21:20 laptop dbus-daemon[2693]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service' requested by ':1.5577' (uid=1000 pid=1013168 comm="/usr/bin/nautilus --gapplication-service " label="unconfined")
11月 06 10:21:20 laptop gnome-shell[9951]: JS ERROR: TypeError: dockManager is null
                                            getRunningApps@/<email address hidden>/locations.js:653:9
                                            wrapWindowsManagerApp/fileManagerApp._updateWindows@/<email address hidden>/locations.js:258:9
                                            wrapWindowsManagerApp/windowsChangedId<@/<email address hidden>/locations.js:250:24
11月 06 10:21:20 laptop gnome-shell[9951]: JS ERROR: TypeError: dockManager is null
                                            getRunningApps@/<email address hidden>/locations.js:653:9
                                            wrapWindowsManagerApp/fileManagerApp._updateWindows@/<email address hidden>/locations.js:258:9
                                            wrapWindowsManagerApp/windowsChangedId<@/<email address hidden>/locations.js:250:24
11月 06 10:21:20 laptop gnome-shell[9951]: JS ERROR: TypeError: dockManager is null
                                            getRunningApps@/<email address hidden>/locations.js:653:9
                                            wrapWindowsManagerApp/fileManagerApp._updateWindows@/<email address hidden>/locations.js:258:9
                                            wrapWindowsManagerApp/windowsChangedId<@/<email address hidden>/locations.js:250:24
11月 06 10:21:20 laptop gnome-shell[9951]: JS ERROR: TypeError: dockManager is null
                                            getRunningApps@/<email address hidden>/locations.js:653:9
                                            wrapWindowsManagerApp/fileManagerApp._updateWindows@/<email address hidden>/locations.js:258:9
                                            wrapWindowsManagerApp/windowsChangedId<@/<email address hidden>/locations.js:250:24
11月 06 10:21:20 laptop gnome-shell[9951]: JS ERROR: TypeError: dockManager is null
                                            getRunningApps@/<email address hidden>/locations.js:653:9
                                            wrapWindowsManagerApp/fileManagerApp._updateWindows@/<email address hidden>/locations.js:258:9
                                            wrapWindowsManagerApp/windowsChangedId<@/<email address hidden>/locations.js:250:24
```

[oh (jigglywiggly)]

Similar problem here, except I am on Wayland. The nautilus files app is on the taskbar, but if I click it, it just opens a new nautilus window, it does not let me cycle between the open ones. If I right click it, there is only the option to remove it.

If I have it removed and open a nautilus window, there is no option to pin it to favorites. I am using Ubuntu 21.10

[oh (jigglywiggly)]

Actually in my case, this is a problem with dash to panel. Does not occur with the default tray.

[JEMYZHANG (jemy-zhang)]

You're right, it's a problem of dash to panel, I found the issue reported on github: https://github.com/home-sweet-gnome/dash-to-panel/issues/1497

[JEMYZHANG (jemy-zhang)]

As comment in https://github.com/home-sweet-gnome/dash-to-panel/issues/1500#issuecomment-962511964, this problem is caused by dash-to-dock not release the hooks of nautilus.

This issue could be fixed by disable-enable the dash-to-panel after editing the /<email address hidden>/docking.js as https://github.com/micheleg/dash-to-dock/pull/1582/files.