This is a very good and helpful addon, but I have a problem. I can't set the amount of closed tabs to 25. No matter what I do, there are only 10 (5 in menu and 5 in kontext menu). Is there a way to fix it?
Please have a closer look at the addon description: https://addons.mozilla.org/firefox/addon/undoclosetabbutton/ You have to increase the value of the preference browser.sessionstore.max_tabs_undo
