project structure changes - where its captured ? change docs does not capture it ?

Hi Gurus,

In PPM Project side structure, if I add or delete a task or modify it, does change documents captures the change ? It does not work this way - i tried.

I know snap shot comparison could be used for this purpose, but do we have any change log where these are logged, if not any other way of getting a report ?

thanks in advance.

Devi