I should have also said that it depends on one's definition of open. For instance, when expo mode was added to Firefox (I was sad to see it go), I used it to ha

I should have also said that it depends on one's definition of open. For instance, when expo mode was added to Firefox (I was sad to see it go), I used it to have about 4-5 groups of 2-8 tabs each, but only was ever actively using one group.