I have noticed occasionally when on this and other sites that questions are closed, even when they have been answered. An example of this is here - here is the closed explanation:

closed as off-topic by karel, Warren Hill, Florian Diesch, Braiam, Eric Carvalho Dec 4 '13 at 2:06

But the OP had already marked this as the answer 22 hours earlier, as shown in the mouseover on the answer tick:

"The question owner accepted this as the best answer Dec 3 '13 at 4:45"

Why would this be necessary, and what would be the point in it? Doesn't marking it as answered close it anyway?

I have noticed occasionally when on this and other sites that questions are closed, even when they have been answered. An example of this is here - here is the closed explanation:

closed as off-topic by karel, Warren Hill, Florian Diesch, Braiam, Eric Carvalho Dec 4 '13 at 2:06

But the OP had already marked this as the answer 22 hours earlier, as shown in the mouseover on the answer tick:

"The question owner accepted this as the best answer Dec 3 '13 at 4:45"

Why would this be necessary, and what would be the point in it? Doesn't marking it as answered close it anyway?