Type name Gjs_Freon_FreonPrefsWidget is already registered

[eitch]

On Ubuntu 20.10 i get this when trying to show the settings. It happens after opening the second time.

Error: Type name Gjs_Freon_FreonPrefsWidget is already registered

Stack trace:
  _init/GObject.Object._classInit@resource:///org/gnome/gjs/modules/core/overrides/GObject.js:451:27
  _init/Gtk.Widget._classInit@resource:///org/gnome/gjs/modules/core/overrides/Gtk.js:95:32
  registerClass@resource:///org/gnome/gjs/modules/core/overrides/GObject.js:95:22
  @/home/eitch/.local/share/gnome-shell/extensions/freon@UshakovVasilii_Github.yahoo.com/prefs.js:20:24
  _init@resource:///org/gnome/Shell/Extensions/js/extensionsService.js:204:33
  OpenExtensionPrefsAsync/<@resource:///org/gnome/Shell/Extensions/js/extensionsService.js:122:28
  asyncCallback@resource:///org/gnome/gjs/modules/core/overrides/Gio.js:132:22
  run@resource:///org/gnome/Shell/Extensions/js/dbusService.js:177:20
  main@resource:///org/gnome/Shell/Extensions/js/main.js:19:13
  run@resource:///org/gnome/gjs/modules/script/package.js:222:19
  start@resource:///org/gnome/gjs/modules/script/package.js:206:8
  @/usr/share/gnome-shell/org.gnome.Shell.Extensions:1:17