Works as advertised and is a useful idea.

There are two features I'd like to see added:

1.) An "Unclose Tab" command so that if I accidentally close the wrong tab, I can get it back. (I do this a lot.)

2.) A ForgetMeNot preference pane, a la the PithHelmet preference pane, so I can turn off the ability to autorecover the last window used when I quit Safari. (That I don't need. The unclose commands are what I'm after.)

But this is quite promising and does exactly what it says it will. Doesn't appear to affect Safari adversely.

Good job.