Clicking on the config tab tends to modify the config, blocking the user until they close the prompt. It may also delete their calendarListData if the access_token has expired since it doesn't support using the refresh_token in that file.
[ ] Update auth_token if expired (move that code from popup into shared).
[x] Only automatically load calendar if open when auth_token changes.
[x] Add refresh calendar list button
[x] Don't persist device_code so users who don't use google calendar don't get annoyed with the tab either.
[x] Add relogin button that deletes the auth_token, triggering the device_code login.
Clicking on the config tab tends to modify the config, blocking the user until they close the prompt. It may also delete their calendarListData if the access_token has expired since it doesn't support using the refresh_token in that file.