I’m trying Ubuntu Disco, works great so far, but it seems there is no way to enable the notification sounds.
The volumes are all fine, and for example the “warning sound” works (it is played for example when using the “search” function of Firefox and searching for a non-existing string, or by running ‘printf \a’ in a terminal). Still the notification from Firefox, Thunderbird (new mail notification), Signal (signal-desktop snap) do not produce any sound. The same happens if I run “notify-send test” from a terminal: the notification bubble appears, but no sound is played.
In Settings -> Notifications, the “Sound Alerts” are enabled for all the applications.
How do I enable the notification sounds?