Steps to Reproduce:
- Log in on gerrit-test.wikimedia.org
- Go in settings
- Make Dark theme (alpha) enabled
When enabled, Gerrit will reload and show UI in dark theme. But, change browser and log in your account.
When you log in your account using another browser, you won't have dark theme and you will have to enable it again.
This can be reproduced and in incognito mode of browser.
If user save some setting on own account, it should be saved always.