Default the folder to “(all)”, since that’s what most people are probably likely to want when they do a search.

I thought the same, but then I saw it also shows deleted messages. I don't want to see those by default.

Also: the link to message inbox from the Chatterbox Nodelet and Fullpage Chat links to the Archive. I don't want that, but it's the only link to the message inbox on those places. I rarely, if ever, look at archived messages. I just want an easier interface to continue a conversation in private. That's not what I get now.