I voted to close a question as a duplicate of this question. After entering the URL, the close dialog displays the question and its answers. In this dialog, I could only see 10 of the 12 answers (one of the 10 having been deleted), and those did not include the accepted answer, which is also the highest-voted answer.
This behavior could lead other potential voters to believe that the question did not have a good answer, and thus not vote to close.
This happens because the question has a large number of answers. It seems like the dialog only shows the ten oldest answers, sorted by votes. Instead, it should show the ten highest-voted answers.