I fixed it by restarting the vm - but now it is back. It looks qubes
related because:
user@personal:~$ ps xa | grep thunder
9461 ? Sl 0:00 /usr/bin/python2 /usr/bin/qubes-desktop-run
/usr/share/applications/mozilla-thunderbird.desktop
9485 ? S 0:00 /usr/bin/sh -l
/usr/lib/qubes/qubes-rpc-multiplexer
qubes.StartApp+mozilla-thunderbird dom0
9486 ? S 0:00 /usr/bin/sh -l
/usr/lib/qubes/qubes-rpc-multiplexer
qubes.StartApp+mozilla-thunderbird dom0
9489 ? S 0:00 logger -t qubes.StartApp+mozilla-thunderbird-dom0
9501 ? Sl 0:20 /usr/lib64/thunderbird/thunderbird
11702 pts/0 S+ 0:00 grep thunder
--
Zbigniew Lukasiak
https://medium.com/@zby
http://brudnopis.blogspot.com/