To start a production job one has to select a publication, and then one can select a production job. In Designer 6 the production job is directly available in the tree, so why not start a job by selection of the production job itself? Now we can only modify the content of a production job, but cannot run it.
This would also reduce the confusion often encountered: The production job uses a publication, is not used by it. So when deleting objects, one first has to delete the production job before one can delete the publication. Users often think the other way because when making a hip, one first has to select the publication.