Ability to undelete anything that has been accidentally deleted.
The system needs to be robust, and this means ability to roll back accidental changes.
Dmitry Buterin commented
Conceptually I fully agree. However, anything is a big word. I don't think I have ever seen a system which would allow you to undelete *anything*. So let's focus this thread - what has prompted you to comment on this? What is the most important object in Wild Apricot to implement this?