If you've come from Google Chrome to here and are trying to find a grouping extension that's similar, this one is! Instead of grouping them in the top bar, you'll have a little sidebar. BUT, the important thing is that it will let you close out of tabs on your main slider without actually deleting them. So, if you don't like having a bunch of windows open or tabs up on your slider, you won't have to!! You can even open one tab at a time or the entire group. An absolute lifesaver for me :)