Slightly unrelated, but since they launched this (still wish it worked for my account, but nevertheless), it gave me idea for this very tiny hack. I have gone through all my cancelled reservations and renamed them. (I usually name all my trips on the website so they are something like: "DFW-LAX Sep")
Since those names have carried over to the cancelled screen, most of those I have renamed to ".", since I can't seem to delete a name. For the ones where I have a future flight credit, I have put "$225.40 sitting here" as the name since there are more cancelled flights listed there than I usually have and it saves me flipping back and forth to the spreadsheet I'm keeping to figure out which ones have $$$ sitting on them.