At first this looked fine, so I merged it, but I've changed my mind. It causes a traceback when using amend when there are no changes in the working directory. And, it really doesn't work -- if you try to only change the commit message, and deselect everything for commit, then all changes in the working dir are committed. It is also technically not necessary, since you can change a commit's comments with 'hg ci -X . --amend'. So, I'm going to backout the change.