virtualbox.org

Hi All!
I have just saw an amazing screen shot of the snapshot function in the help content of Vbox 3.2.6 and in which shows that several snapshots can derive from one base snapshot. It seems really useful. But I can't get the way to make it. So could anyone tell me how?

I just figure out that it's the new feature of Vbox 3.1 n later version. Simply restore to one of the snapshot created before then a branch of time line can be created! It's really amazing!