Pressing & holding Ctrl key while pressing Tab key in Firefox usually switches tabs opened in the browser. Now adding on top of that, you can actually preview what’s in tab before switching to it.
The feature is disabled by default in Firefox 3.6 and here is how you can turn it on.
1. Type about:config in the address bar and press Enter.
2. Search for ctrlTab in the filter box, and double-click browser.ctrlTab.previews until the value says true.
The change takes effect immediately. Once the change has been made, you can start enjoying the tab preview feature in the browser. Those who often have more than 10 tabs open in the browser will benefit from it the most.
On the preview popup, you can even do a search to help find the tab you are looking for much easier. Simply switch to Show all tabs first, and type in the words in the search box at the top of the Preview window.