Accidentally happened upon this Firefox gem today: If you click a bookmarks toolbar folder with your mousewheel, the ‘fox will open all the sites up for you in tabs. (If it’s a long list of bookmarks, Firefox will politely ask if you really want to do that.) Of course, you can also open links in a background tab with the mousewheel, and close background tabs by mousewheel-clicking on them. These shortcuts are worth upgrading to a new mouse alone. Here are more tips on working with groups of tabs in Firefox.