Make sure that you are using Firefox and many of your tabs are open, sometimes you do not know what each bothers are.
Tab preview is a simple name that collectively tells everything about this useful add-on which will add a preview to each tab when you place the mouse over them.
In this way, you can find out which website you are going to on the tab that you are going to and you will save a lot while surfing the net if you are one of the users who usually have seven tags open.
Finally, forget about configurations and settings, install it and use it. Give it a try as it is easy and useful