It might depend partly on how long it is since you last used Ancestry, but also whether you are using the same IP address. Most broadband connections do not provide a static IP address, but I don't know the circumstances under which it might change.Thinking about it, I’m not at all convinced that keeping tabs open (or not) has anything to do with being logged out of Ancestry. We’ve never kept multiple tabs open permanently on any of our devices at Ancestry (or any other site), but it’s only in the past couple of months I’ve started being logged out occasionally.