I have tried this as I have been able to do this before in previous releases, both as explained below.
The Option to Delete via the Right-Click Menu is gone and to delete when selecting the Surface and applying the delete key does nothing.
I have tried this in all Views that have been setup for this Project, i.e, Plan / 3d / Station View.
The only way I have found to Delete a Surface is to Select in Graphics and Apply the Delete Key.
When a Surface has been Canceled or has Errors and cannot be viewed Graphically, then I used to be able to Delete as you have suggested in the Project Explorer.
Please Advise.
Thanks for your assistance.