In this question the "Related" sidebar contains this. But that question was marked (rightly so) as duplicate on November 28, 2013 (3 months ago, so there isn't the excuse that it was selected before being deemed duplicate). If we want to weed out duplicate/redundant questions, this shouldn't happen. I often look up the related questions, and sometimes had comments or supplementary answers for them, which are closed for duplicates AFAIU.
Or is there a rationale for this I don't see?