Rose: Check your preferences (on Windows they are under the tools menu, I think. On Linux they're under the edit menu) -> Privacy. If there is a checkmark before "Always clear my private data when I exit Firefox", you might uncheck it, or click on Settings and uncheck "saved passwords" and "cookies". The former checked means that the passwords from the password manager are deleted, and the latter means that the information Brainking stores in a cookie, are also deleted. If you have checked "remember user name and password" on the login page, this information is stored in a cookie.

For the style switching: There are three links: "To simple style", "simple" and "castle". The latter two change the style but don't save it, only the first option saves it in the database.