Chromium complains that it's not the default browser when it is the default according to Gnome Settings

Could it be that you have installed chromium both from ubuntu packages and from the snap, by any chance?

Can you share the output of the following command, run in a terminal?

    xdg-settings get default-web-browser

Hi Olivier,
No, I hadn't tried to install chromium at all - I merely used the one version of chromium which came bundled with Budgie.

The output of that command was:
firefox.desktop
...which is interesting, given that by default, chromium is the only browser installed in Budgie - at least in the daily builds.

Thanks,
Ken.
***

That's interesting.

If you close gnome settings, open it again, does it consistently say that the default browser is chromium? What are the other options in the dropdown? Can you confirm that firefox is not installed by sharing the output of the following command:

    apt policy firefox

It looks like it might be an issue with budgie's default settings that default to firefox (the ubuntu default) instead of chromium.

Firefox is not installed, so I think your final point is likely to be correct.

apt policy firefox
firefox:
  Installed: (none)
  Candidate: 57.0.1+build2-0ubuntu1
  Version table:
     57.0.1+build2-0ubuntu1 500
        500 http://au.archive.ubuntu.com/ubuntu bionic/main i386 Packages

I can confirm it's a bug in budgie. I installed the latest ISO in a VM, and am seeing that after first login, not having launched any application except for terminal:

ubuntu@budgievm:~$ xdg-settings get default-web-browser
firefox.desktop
ubuntu@budgievm:~$ apt policy firefox
firefox:
  Installé : (aucun)
  Candidat : 57.0.1+build2-0ubuntu1
 Table de version :
     57.0.1+build2-0ubuntu1 500
        500 http://es.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
ubuntu@budgievm:~$ apt policy chromium-browser
chromium-browser:
  Installé : 65.0.3325.146-0ubuntu1
  Candidat : 65.0.3325.146-0ubuntu1
 Table de version :
 *** 65.0.3325.146-0ubuntu1 500
        500 http://es.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

I've no idea what needs to be overridden to change the xdg-settings for the default-web-browser. If anyone knows please shout.

Well, there's another path - changing the default browser back to Firefox, which would be my personal preference... ;)

I'm wondering if something in xdg-utils has regressed as per this bug report https://bugs.launchpad.net/ubuntu/+source/chromium-browser/+bug/1509139

It looks highly likely (to my less-than-expert-eye anyway) that the bug you've linked to is the same issue...

Has this issue been fixed yet?