One thing you will notice with a tab that has workflow - you cannot edit or delete records anymore. This is because the list is now considered under the control of workflow, and shouldn't allow for manual edits.

However, you can override this. When you add workflow to a list, it adds three flags to the form: Disallow Edit, Disallow Create and Disallow Delete.Simply remove those flags so you can delete records, then you can put them back afterwards.

There is also the flag "Admin Edit Only" you can add instead - which allows an administrator to edit the record, but not a regular user.