Keep the Admin tab left tabs when user browse a workflow model

Workflow models are accessible from Admin > Workflow.
When user clicks on a workflow, the left column is not the Admin's columns, but the Workspace left column (with tree, worklist, etc.). Although this makes sense because workflow models are documents, it would be more user friendly to keep the Admin tabs so the user remains in the same visual context.

More generally, shouldn't we disable some actions on workflow models, such as "add to collection"?