The same as now, except the top comment remains visible. It's rare that individual comments on HN are too long. The correct way of dealing with long individual

The same as now, except the top comment remains visible. It's rare that individual comments on HN are too long. The correct way of dealing with long individual comments is by showing only the first N characters and allowing expansion with an ellipses. But a workaround in my proposal is to collapse its parent. (This wouldn't work if it's a top-level comment, or if the parent had other replies you wanted to read.)