Causes problems with GNOME shell in Ubuntu Cosmic (3.30.1)

Created by: ruedigerkupper

The current version of hamster shell extension can be installed in Ubuntu Cosmic Cuttlefish (GNOME 3.30.1) and initially seems to work. But it causes issues with screen locking and frequently kills GNOME shell:

• when locking the screen while hamster shell extension is running, the screen goes all lilac and nothing happens. Only pressing Super+L again brings up the proper lock screen.
• when unlocking the screen, all shell extensions are gone (including the Ubuntu dock on the left)
• restarting GNOME shell usually crashes the shell and logs out the user

Can you make the shell extension act nicely in GNOME 3.30.1?