This bug was fixed in the package gnome-tweaks - 3.30.2-0ubuntu1
--------------- gnome-tweaks (3.30.2-0ubuntu1) cosmic; urgency=medium
* New upstream release - Fix running Tweaks outside of GNOME Shell (LP: #1799459)
-- Jeremy Bicha <email address hidden> Sun, 09 Dec 2018 22:03:19 -0500
This bug was fixed in the package gnome-tweaks - 3.30.2-0ubuntu1
---------------
gnome-tweaks (3.30.2-0ubuntu1) cosmic; urgency=medium
* New upstream release
- Fix running Tweaks outside of GNOME Shell (LP: #1799459)
-- Jeremy Bicha <email address hidden> Sun, 09 Dec 2018 22:03:19 -0500