1. Go to Configurartion->Website->Themes section. See that there are AddedOn and DeletedOn fields in the grid and in the edit form. See that no "Delete" button over Themes grid.
2. Click on Status field search filter - see that field has "Deleted" option.
3. Copy simple theme folder with all underlying files to the "simple2" folder under the same themes folder. Press "Rescan Themes" button in the "Themes" section, see that simple2 theme appeared in the Themes section and AddedOn time points to the current time, when addition happened.
4. Delete "simple2" folder. Press "Rescan Themes" button in the "Themes" section, see changes of simple2 record in the Themes section:
4.1. Status changed to "Deleted".
5. Open some theme on edit. See that Name field is readonly.