Suggestion: Use MATE applications in the eventual Unity 7 flavor of Ubuntu 18.04

Hi everyone!

I just came across this article and how there’s now a testing image for Ubuntu 18.04 using Unity 7.

I want to suggest the team to try and use MATE default applications for a potential Ubuntu Unity remix flavor, instead of those provided by GNOME. That’s how I’m using Unity in 16.04, with the exception of Caja, which doesn’t integrate properly with Unity in 16.04.

The reason why I think MATE apps are more appropriate is because they don’t use CSD and work very well with the global menu.

It also seems to me that nowadays MATE’s design and usage paradigm is closer to Unity’s than GNOME’s: CSD applications don’t look right in Unity, and defeat the point of a global menu, in my opinion.


This is a good point, in order to take full advantage of Unity’s global menu feature we need applications that will use the global menu as intended.

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Write more about this, please. We may have to leave nautilus sitting in the background, even if we won’t use it. I would like to know how to make Caja take over the desktop?

I’m the project lead for Ubuntu MATE and an upstream MATE Desktop core team member. I’d be happy to support this endeavour. :slightly_smiling_face:

I’ve just (like an hour ago) had a conversation with the Xubuntu team in #xubuntu-devel on IRC. They are planning to do something similar and have voted to use MATE Calculator, Engrampa (archive manager) and Atril (document viewer) in Xubuntu, replacing the GNOME3 equivalents. I’ve quickly reviewed the some of the MATE application packages and didn’t find any significant blockers other than “MATE” prefixing some of the application names, something I’ve long wanted to address but can also be overcome with DE specific .desktop files delivered via patches in the debian/ packaging.

During the 17.04 cycle, Ubuntu Kylin (tuned to the needs of Chinese users) created a new desktop environment called UKUI which is built on top of MATE. So, I’m more than happy to collaborate with other flavours.

My initial thoughts are stick with Nautilus for the file manager, it will require some careful evaluation to see if Caja can be integrated. Leaf applications such as Pluma (text editor), Engrampa (archive manager), Eye of MATE (image viewer), Atril (document viewer), MATE System Monitor and MATE Terminal could all be used without issue.

If this is something the Ubuntu Unity team want to pursue I’m happy to help :slightly_smiling_face:


I think this Is a great idea . I’d go as far as to use the welcome and boutique from U mate . Re skinned of course

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Good job I know you have a sensible clock - eg a UK one, luckier you were about. Good to have you show and answer our question - and then come back while we were all still meeting with some data - kudos.


I’m not a programmer, so I can’t say much else, except that I’m using all those as defaults with Unity in 16.04, with the exception of Caja. I ended up using Nemo from this PPA which integrates nicely with Unity, but it was patched to do so.

I’ve tested this quite a while ago, but if I can recall, it’s possible to make Caja as the default file manager with Unity, by doing something like:

gsettings set org.gnome.desktop.background show-desktop-icons false
xdg-mime default caja.desktop inode/directory application/x-gnome-saved-search

The problem is that if you add it to the Unity launcher, it won’t have the the expected launcher items (also, it will pick up the “Nautilus” icon, not the “Files” icon), and when it draws the desktop, it will pick the wallpaper set up in the Ubuntu MATE session.

While I understand that keeping Nautilus as the file manager would be a simpler solution, I do wonder if the Nautilus that will land on 18.04 will also need to be patched in order to retain Unity7 compatibility.

Thank you for that!

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About caja in Unity, It can be done if we can patch ucc to draw wallpaper & icons with caja. We had similar discussion with nemo too.

Also there is gnome-user-share. We need to do something about it. The issue is that, the new version of gnome-user-share doesn’t have a GUI (merged with GCC) and @jbicha proposed that if we could use mate-user-share preferably without caja in Unity. Is it possible?

All things are possible given enough effort. Let me have a little experiment with mate-user-share and report back.

With regards to Caja itself, there is lots to consider and test. There are options to modify Caja’s behaviour when not running as part of a MATE session. This needs careful evaluation.

What Ubuntu Unity iso image is considered “official” by the team? I’m happy to do some testing to see what might be possible.

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This mate-prefix is bit troublesome, even in Mate. For example, if you write terminal (or part of it) it doesn’t immediately point to mate-terminal.

Hello everyone,

I also think that Mate apps is the proper way. The CSD and headerbar stuff will be very difficult to maintain. Mate apps are already maintained by the Mate team. I think that for 18.04 the switch must be done. The only thing that must be considered is whether to use Caja or a patched Nemo. Or maybe keep nautilus until 18.10 with another file manager installed by default(caja or nemo). Something like gnome-terminal and xterm lived together for years.
I think also that unity-tweak-tool must be installed by default and there must be basic integration in unity-control-center (like gufw).
It seems that everything related to gnome will be difficult to maintain. The apps will look even uglier in other DEs. I tried gnome-calendar in XUbuntu 16.04 and it was disaster. Huge bars, almost unresizable.


I certainly up-vote this suggestion. MATE applications are more friendly to Unity than GNOME’s.
And I’m glad Martin jumped in right away. :slight_smile:


I also would like Mate apps to be with the future Ubuntu-Unity. It would be nice to have Caja to be the File Manager, and take over the desktop.

Only, even in Mate, take off the word Mate in front of Mate Calculator, Mate Terminal, Mate System Monitor, Mate Dictionary and so on. Let they be Calculator, Terminal, System Monitor etc, and let everyone know, if they use Mate, they are getting everything Mate, so they don’t have to keep on writing Mate.

Let Caja be just Caja, so everyone knows it is the file manager, but if anyone write (in search) file m…, it should open Caja. Right now, we get an app called “File Management,” not Caja. When you write Text…, you get Pluma, but not as the first choice, so writing Text and clicking Enter won’t open Pluma.


Just having a coffee and a play with mate-user-share on Ubuntu Unity. It’s stands alone and making some minor changes to the .desktop file exposes it in Unity Control Center. That modification could be carried as a distro patch or upstreamed.

Proof it happened


As for Caja, I will look into to this. Like I say, this does need some careful evaluation. I’ll report back when I have findings.

MATE prefixing

You don’t need to convince me that the MATE prefixes on some application names is ugly. I completely agree. I’ll start the conversation upstream to drop that.


I tried to suggest to use MATE DE as default desktop on ubuntu-desktop mailing list in Bionic Beaver, but with no luck.

But anyway the OP idea is great.
I wrote this message from Ubuntu 16.04.3 LTS with MATE DE and I’m very happy with it, it just works.

Thank you, Martin @Wimpress, and whole MATE team!


I have spent 10 minutes integrating Caja with Ubuntu Unity, so this is far from exhaustive research. However, I have completely removed Nautilus from the system and have Caja handling desktop management. This is what it looks like:

How to replace Nautilus with Caja

To reproduce this do the following:

Unlock the entry for Nautilus in the Unity dock. Run the following from a terminal:

sudo apt install caja caja-sendto dconf-editor
sudo apt purge nautilus nautilus-sendto

Create /etc/xdg/autostart/caja-autostart.desktop with the following contents:

[Desktop Entry]
Exec=caja --force-desktop --no-default-window

Create /usr/share/applications/caja-unity.desktop with the following contents (I’ve removed translations for clarity):

[Desktop Entry]
GenericName=File Manager

Run the following in a terminal:

sudo update-desktop-database

Search for Caja in the dash, open it, lock Caja to the Unity Dock and move it to the top slot. Use dconf-editor to change the picture-filename to /usr/share/backgrounds/warty-final-ubuntu.png in /org/mate/desktop/background.

Now reboot. When you log in Caja should be managing the desktop.

All of the above can be accomplished automatically via simple packaging changes and gschema overrides.

What doesn’t or might not work

  • Right clicking on the desktop provides an option to Change Desktop Background which attempts to launch mate-appearance-properties. That will need a patch to launch to appropriate Unity alternative when the desktop session is Unity.
  • Any nautilus-thing extension would need to be replaced with Caja alternatives. For example, caja-sendto.
  • Does Unity Control Center expose UI to configure Nautilus? If so those would need changing to reference Caja. caja-file-management-properties.desktop could also be modified so it is exposed in Unity Control Center. Trivial, but not essential.
  • There are likely mime types configured to make Nautilus the default file manager. Those would need changing to reference Caja.
  • There are likely many other integration points, your test feedback is welcome :slightly_smiling_face:

It seems that switching to mate apps is acheiveable for 18.04. Very impressive!

Right clicking won’t change background, but everything else work.
Everything in Unity Control Center works.
I don’t know where are the mime types, to check them.
On right clicking inside Caja, Open Terminal here is not there.
Right Click>Create Document opens a list of all documents in all folders in Home and “Empty File,” only on the bottom. This happens within Caja and on the desktop. That right click has to link only to “Empty File,” not to show all documents.

EDIT: Checked again. That Right Click>Create Document opens a list of all documents in Templates, not all documents in Home.
Checked with Ubuntu Mate, right clicking inside Caja, you can open the Terminal and also Open Caja as Administrator. These are not in Caja in Unity.

To add the Open Terminal context menu do the following, which will also install mate-terminal:

sudo apt install caja-open-terminal

To add the Open as Administrator context menus, which will also install pluma as it includes an Edit as Administrator feature:

sudo apt install caja-admin

Here are some of the other Caja extensions that are available:

  • caja-admin - Add administrative actions to Caja’s right-click menu
  • caja-dropbox - Dropbox integration for Caja
  • caja-gtkhash - caja extension for computing checksums and more using gtkhash
  • caja-image-converter - Caja extension to mass resize or rotate images
  • caja-open-terminal - Caja plugin for opening terminals in arbitrary local paths
  • caja-rename - Batch renaming extension for Caja
  • caja-sendto - integrates email clients and Pidgin into the Caja file manager
  • caja-share - Allows one to quickly share a folder from the Caja file manager
  • caja-xattr-tags - Allows one to view extended attributes
  • deja-dup-caja - deja dup extension for caja file browser
  • folder-color-caja - folder color for caja

@tsimonq2 Is currently working on bringing caja-eiciel and caja-seahorse to the Debian and Ubuntu archives.

The default mime type file associations are in /usr/share/applications/defaults.list which is a symlink to /etc/gnome/defaults.list. If MATE applications are to be used that will need modifying and Ubuntu Unity would need to ship their own version of defaults.list in a settings package :slightly_smiling_face:

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I’ve just noticed that notify-osd is missing from the Ubuntu Unity image @chanath @khurshid-alam @dale-f-beaudoin

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