It is a good idea to maintain a change log. It is also good to have it presented whenever saving a job change.
However, it would be helpful if there were a "Cancel" button on the dialog in case there is something forgotten or any other reason not to save the job at that point in time.
In a broader scope, it would be interesting to have jobs and groups checked in and retrievable from a version control repository such as Subversion, git, Mercurial, etc. In the best case, it would be possible to "check in" a group from development and "check out" the group to a test or production branch of the adTempus heirarchy.