Increase The Amount of Firefox Recently Closed Tabs Shown

Type “about:config” in your Firefox address bar and hit the Enter key.








type or copy and paste “max_tabs_undo” in the Filter box and hit Enter.

Double click “browser.sessionstore.max_tabs_undo” or right click and select modify.

Enter the number of tabs you want shown in Recently Closed Tabs and click OK. The default value is 10, I use 20.