nemo-desktop does not show background on GNOME FlashBack session

[Norbert]

Steps to reproduce:
1. Install Ubuntu 18.04 LTS
2. Install `gnome-panel` and `nemo` packages
3. Disable nautilus-desktop with `gsettings set org.gnome.desktop.background show-desktop-icons false`
4. Remove `nautilus-desktop` with `sudo rm /usr/bin/nautilus-desktop`
5. Log-out and log-in back
6. Set `gsettings set org.nemo.desktop ignored-desktop-handlers "['conky','nemo','nemo-desktop','nautilus','nautilus-desktop']"` to prevent this warning

** (nemo-desktop:xxxx): WARNING **: Desktop already managed by another application, skipping desktop setup.
To change this, modify org.nemo.desktop 'ignored-desktop-handlers'.

7. Put some files to ~/Desktop folder with `touch ~/Desktop/x ~/Desktop/y`
8. Try to launch `nemo-desktop`

Expected results:
* nemo-desktop maintains desktop, its shortcuts and background

Actual results:
* nemo-desktop does not maintain desktop, its shortcuts but not background

(nemo-desktop:xxxx): Gtk-WARNING **: Failed to register client: GDBus.Error:org.gnome.SessionManager.AlreadyRegistered: Unable to register client

(nemo-desktop:xxxx): Gtk-WARNING **: Allocating size to NemoWindowPane 0x55632786f3c0 without calling gtk_widget_get_preferred_width/height(). How does the code know the size to allocate?

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: nemo 3.4.7-1ubuntu1
ProcVersionSignature: Ubuntu 4.13.0-17.20-generic 4.13.8
Uname: Linux 4.13.0-17-generic x86_64
ApportVersion: 2.20.8-0ubuntu6
Architecture: amd64
CurrentDesktop: GNOME-Flashback:GNOME
Date: Tue Jan 9 19:55:25 2018
InstallationDate: Installed on 2017-12-22 (17 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20171221)
SourcePackage: nemo
UpgradeStatus: No upgrade log present (probably fresh install)

[Khurshid Alam (khurshid-alam)]

Flashback also uses gnome-settings-daemon. May be that's why it can't work. What happens when you restart gnome-settings daemon?

[Norbert (nrbrtx)]

Without killing `nautilus-desktop` and after launching `nemo-desktop` both them control desktop - I have two sets if icons with background.

I think that main problem is that GNOME FlashBack ignores `gsettings set org.gnome.desktop.background show-desktop-icons false`. Setting this option does not remove icons from desktop.

`nautilus-desktop` is auto-launched with `nautilus-desktop --force` which means "Always manage the desktop (ignore the GSettings preference)."
It seems to be launched from `/usr/share/applications/nautilus-classic.desktop` file.

Hacking this file by replacing `nautilus-desktop --force` to `nemo-desktop` with
`sudo sed -i 's/nautilus-desktop --force/nemo-desktop/g' /usr/share/applications/nautilus-classic.desktop`
helps, but still there is no wallpaper.

[Alberts Muktupāvels (muktupavels)]

gsettings set org.gnome.gnome-flashback desktop-background true

It is disabled on Ubuntu because nautilus in Ubuntu was still drawing background. If nemo-desktop does not draw background image you need to enable it.

[Norbert (nrbrtx)]

Here is complete and working solution. `nemo-desktop` is fully-functional on Ubuntu("Unity") and GNOME FlashBack session:

# for GNOME FlashBack session
sudo apt-get install nemo gnome-panel -y

sudo rm /usr/bin/nautilus-desktop
sudo sed -i 's/nautilus-desktop --force/nemo-desktop/g' /usr/share/applications/nautilus-classic.desktop

gsettings set org.nemo.desktop ignored-desktop-handlers "['conky','nemo','nemo-desktop']"
touch ~/Desktop/x ~/Desktop/y

gsettings set org.gnome.gnome-flashback desktop-background true

# for Ubuntu session "Unity"
cat << EOF > ~/.config/autostart/nemo-desktop.desktop
[Desktop Entry]
Type=Application
Exec=nemo-desktop
Name=nemo-desktop
EOF

Hope this helps somebody.

[Launchpad Janitor (janitor)]

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

[Uriel Tunn (u2n)]

Thanks @Norbert. Confirming this bug is still present in the latest 18.04 release and your workaround still fixes it.

Actually spent many hours trying to do this "properly," both directly and by searching. Nothing worked and found no solution.

Two thoughts:
- The key seems to be modifying the Nautilus shortcut to call Nemo instead.

- This is the last bit of integration needed FWICT; seems so simple can't believe it's not done yet!

Sad the Nautilus team gutted it back when Unity was coming on. It was the very best file manager in the Linux world IMO. Still is, but under the Nemo banner (albeit lacking the dual location bars in dual pane mode). Very grateful to the Nemo team for carrying it forward.

Would very much like to see Nemo adopted by Gnome, eliminate these workarounds.

[ubuserone (ubuntu-fm)]

The bug (No wallpaper) still present on 20.04.1 when Nemo on Flashback.

The step guide by @Norbert does not work on 20.04.1

[Alberts Muktupāvels (muktupavels)]

On Ubuntu 20.04 if you want use 3rd party desktop app you need to disable builtin desktop functionality in gnome-flashback. You can do that with:
gsettings set org.gnome.gnome-flashback desktop false

That also disables background handling! If 3rd party desktop app does not draw background you can tell gnome-flashback to draw background on root window:
gsettings set org.gnome.gnome-flashback root-background true

[Erick Brunzell (lbsolost)]

Thanks Alberts. I'd been trying to figure that out for some time now.

[lesliek (lesliek)]

Norbert provided (#5) what he said was a complete and working solution for v 18.04 and Alberts updated Norbert's solution (#9) for v 20.04.
I want to adopt the updated solution, so that I can continue to use my desktop as I have for decades now. (I'm old and resist change as much as possible.)
It calls for me to remove /usr/bin/nautilus-desktop, but I have no such file in /usr/bin/, although I do have other files with "nautilus" in their name.
Can the file nautilus-desktop have been removed and replaced in 20.04?
I'd be very grateful for any assistance.

[Uriel Tunn (u2n)]

@lesliek, also a longtime user here, always Ubuntu w/ gnome-panel (called by different names over time, currently "Flashback"). Every few years I've checked in on Mint and finally switched over ~2 months ago. Quickly realized that all of the patches and workarounds (such as this very one!) I'd been applying were no longer needed. For a classic desktop, everything just works.

A little change can be quite beneficial.