This is pretty well an essential add-on. Who doesn't have a bunch of various tabs they need to open for specific activities. For example, to do your banking, to search for best hotels, to search for best pricing. This add-on lets you set up commonly used groups of tabs and does an excellent job keeping things straight forward and simple. THANK YOU for a great add-on.

*** The one thing I did notice is that when loading Simple Tab Groups for Firefox on a Mac is that the Simple Tab Groups gets buried and as a result, you can't find the STG icon. Search in your bookmarks, it's there. Then drag it to a visible part of your bookmarks bar. Next, right click and click Pin To Toolbar. There, the icon appears !