Deleting items when defining levels

I'm deleting/adding several levels on a client to clean up how it looks. However, I got an error message that I cannot delete an item (that I thought was empty). It would be very helpful if the error message could state WHAT was deleted. I had to go one by one to figure it out since I did delete several unused levels as well.

PLUS it would also be helpful to be able to re-input the level deleted in error, so I don't loose my work. Instead I am required to cancel the changes and updates I made, just so I can keep the level I tried to delete in error, even though I put it back as if it was a new level with the same name, ID and description.