How does one update a question's status?

How does one update a question's status?

I asked a Q in the Using jQuery forum, received two answers, which I marked as "answering the question", but the status shows "Working On It".  Who controls the status setting? moderators?
I thought the status should switch to "answered" once I selected an answer, but it didn't.

I selected one answer as "best"... to see if that would help.  Now there is a green checkbox, but the status is still "Working On It", which seems a bit counter intuitive:  a green check and "working on it".