Currently, the banner that appears after a user has switched languages using the top right dropdown menu is displayed in the language that was set previously. Instead, the banner should use the new language selected by the user, both for consistency with the rest of the UI and because the user might genuinely not understand the previous language and therefore won't understand what the banner says.

I also wonder whether the message should read simply "Language set." for English, as the source text cannot be improved by translators via Transifex.