Windows 7 shows thumbnails preview of all windows of same kind (actually same windows class). But Firefox, by default, does not allow this for all sites open in its different tabs. By default, Firefox shows only one thumbnail of the presently visible tab. But a using little tweak you can make it show thumbnails of all the sites open in different tabs as follows :
- Open Mozilla Firefox
- Type about:config in the location bar and press Enter.
- You will see a warning box, click on I’ll be careful, I promise as shown
- Use the filter box to look for the entry browser.taskbar.previews.enable
- By default the value of this entry is false, double-click on it to make it true.
- Restart Firefox
Now you would see thumbnails for every tab in Firefox in the taskbar.