When you click an added or deleted entry in the timeline, Versions
downloads the file from the repository to a temporary location and
then tries to open it through NSWorkspace.
This attempt fails when your Mac (launch services) can't find a
suitable program to open a file with that file's
I find the Timeline great at monitoring the changes made to various
open-source projects. However, for newly-added files, clicking the
file doesn't do anything. Modified files open up in FileMerge since it
has something to compare against (the previous version). Versions
attempts to do something
