I've taken a bit of case to debug my xfce issue where I'm using notify- osd and it might be a different problem
What's the output of $ gdbus call --session --dest org.freedesktop.Notifications --object- path /org/freedesktop/Notifications --method org.freedesktop.Notifications.GetCapabilities in your environment? In the notify-osd case it's missing the 'action' capability which was the problem but I expect that's probably not the case under KDE -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to thunderbird in Ubuntu. https://bugs.launchpad.net/bugs/2056481 Title: [snap] Thunderbird does not support native notifications on KDE Plasma Desktop Status in thunderbird package in Ubuntu: New Status in xdg-desktop-portal package in Ubuntu: New Bug description: After testing and upgrading, I have discovered that the thunderbird snap does not support native notifications on KDE Plasma Desktop on either Kubuntu or Ubuntu Studio (same packages and desktop, really). This might be an issue with xdg-desktop-portal, so I'm also going to mark it as affected. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/thunderbird/+bug/2056481/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp