mate-session starts instead when i3 was selected on login screen

It seems that ~/.dmrc

$ cat .dmrc
[Desktop]
Session=i3-with-shmlog

is ignored or not written, or something similar.

So the workaround is a bit horrible and MATE-destructive:

```
sudo apt autopurge mate-session-manager
```

What does this command output:

sudo grep Session /var/lib/AccountsService/users/$USER

After entering to "i3" it says:

```
$ sudo grep Session /var/lib/AccountsService/users/$USER
Session=mate
XSession=mate
```

So there is something wrong with new arctica greeter.

After removing mate-session-manager it shows the following:

```
$ sudo grep Session /var/lib/AccountsService/users/$USER
Session=mate
XSession=i3
```

And I think that "XSession" is what counts.

Does it help if you switch to lightdm-gtk-greeter (but keep mate-session-manager)?

Yes, it works with `lightdm-gtk-greeter`.

Ok, then we seem to have defined the problem: There is a need to make arctica-greeter play well with accountsservice.

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

This bug exists in hirsute daily-builds as well.

It may seem strange or coincidental but installing 'fluxbox' helps. With fluxbox installed on the system, we can choose and login to i3. Thereafter, we can login to any session meaning .dmrc is written to correctly. If I uninstall fluxbox, I can only login to i3 if the last login was already i3 (i.e., .dmrc or AccountService file are not overwritten). Once I login to MATE session, thereafter I cannot login to i3.

I tried this with openbox first but it did not make any difference. Didn't check other WMs. Seems fluxbox brings in some conf changes that helps i3 to write to .dmrc/AccountService files.

Still happens in 21.10.

Bug still exists in latest Ubuntu MATE 22.04 LTS.

Bug still exists in latest Ubuntu MATE 22.04 LTS.