Tim has made a couple of improvements to the way that comments are displayed on merge proposals.
The first is pretty simple but makes it far easier to see which merge proposals need attention. Up until now, if you gave your merge proposal a description it would show up as a comment. This made it harder to see which merge proposals had zero activity.
The other change affects merge proposals that supersede another merge proposal. The merge proposal page explicitly states that it supersedes a previous proposal.
It also lists all the comments from that previous review, giving them a yellow background and a link to the superseded review so you can easily tell them apart from comments on the current review.