Finally I can open Gmail tab and be sure not to stumble into any mailbox left open by my wife or son previously.
Delayed autodelete is also precious, just set it to a quite long time (i.e. 5 or 10 minutes) and you can still reopen that mailbox tab you have mistakenly closed, without having to retype your credentials.
Thanks so much for this addon!
PS. A BlackList feature would also be appreciated. I often need to delete cookies only for particular sites (i.e. webmail sites, social networks, etc.).