When you first create assignments, they are stored in Working Copies. When you publish it, it moves to Published Copies and becomes Active. After the Due Date, then it becomes Inactive. Depending on your settings, students who have not started the assignment can still do it. Also, assignments that have been retracted, either manually or automatically, move to the Inactive category. You should keep in mind, however, that you cannot publish two assignments with the same name. If you want to edit a published assignment, click directly on the name in the Active category.