– In the ‘Filter’ box, type ‘browser.allTabs.previews’, Double-click its entry and change its value to ‘true’.
– Similarly find browser.ctrlTab.previews, Double-click its entry and change it value to ‘true‘
– Close the configuration tab. Now you will notice the small ‘All tabs’ icon the extreme right in the tool-bar. Click it. or press Ctrl+Shift+E key.
– Once you click the ‘All Tabs’ button, all the tabs will get listed just below the toolbar in a considerably large thumbnail previews.
You can also access Tab preview by pressing Ctrl+Tab key.
That’s it !!! You are done.