I've been comparing session manager types of add-ons, because I use a lot of tabs. With this one, it didn't *appear* to have the "lazy loading" feature, where pages aren't reopened until you click on them. Other session manager-style add-ons (tab session manager, mysessions) have this. I restored 300+ tabs with OneTab, and it used all my memory, and brought the machine to a halt. I waited for all the pages to load, and finally gave up. No one needs to use 300 tabs at once! Doing the same operation with tab session manager (for example), the 300 tabs open almost instantly, with minimal memory use.