Since updating to Firefox 27, undo close tab has ceased functioning.
All the other restore features work as far as I can tell, and disabling the only addon that should even remotely be affecting it (Tabmix Plus) does not solve the problem. I have also attempted to implement the suggested fix for this article (https://support.mozilla.org/en-US/questions/978286?esab=a&s=undo+close+tab+not+working&r=0&as=s) to no avail.
Wubrane rozwězanje
No problem with https://addons.mozilla.org/en-US/firefox/addon/tab-mix-plus/versions/?page=1#version-0.4.1.3
Maybe the problem is in the latest TabMixPlus
Toś to wótegrono w konteksće cytaś 👍 0Wšykne wótegrona (3)
Did you check the browser.sessionstore.* prefs?
You can reset browser.sessionstore.* prefs that are user set (bold) to the default value via the right-click context menu on the about:config page to make sure that Session Restore is enabled and working properly.
There are other things that need your attention.
Note that your System Details List shows that you have a user.js file in the profile folder to initialize some prefs each time you start Firefox.
The user.js file is only present if you or other software has created it, so normally it wouldn't be there. You can check its content with a plain text editor if you didn't create this file yourself.
The user.js file is read each time you start Firefox and initializes preferences to the value specified in this file, so preferences set via user.js can only be changed temporarily for the current session.
Delete a possible user.js file and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js
Wubrane rozwězanje
No problem with https://addons.mozilla.org/en-US/firefox/addon/tab-mix-plus/versions/?page=1#version-0.4.1.3
Maybe the problem is in the latest TabMixPlus
Sorry, 0.4.1.3 IS the latest TabMixPlus... it is the currently the development version.