"Recently closed windows" greyed out after restart about undoclosetab

[M-Reimer]

That's because of a bug in Firefox that isn't fixed for months. You can either have the built in menu work or an Add-on.

I have to use a workaround to make the API for closed tabs reliable. I copy the list in Firefox in my own memory and then clear it. This is to prevent IDs from duplicating.

But basically your issue is duplicating #79
Maybe we should move any discussion about this topic there.

[M-Reimer]

OK, actually I was a bit optimistic with "for months". It isn't fixed since around 5 years actually... 😞
https://bugzilla.mozilla.org/show_bug.cgi?id=1538119

I think I've explained the issue several times, now, but in a nutshell:
To access closed tabs, Mozilla uses an "ID" which is basically a rising counter starting with the browser start. When a new tab is closed, this counter is increased by one and added to the newly closed tab as its ID.
The problem with this: As soon as you restart the browser, the ID counter starts from zero, again. So now ID "1" could point to a tab of the previous session and the current session making it random which one you restore when clicking the "Restore Tab" button.

To work around this problem, I clear the Firefox internal list to force the IDs to actually be unique, as they now can only point to tabs from the current session.

So far I have not found any way to create a better workaround and it seems like the bug in Firefox does not really get much attention.

[ErikvO]

Thank you for your reply.

I have indeed seen the bug that has been created 22nd of march 2019 and still has not been fixed. I've been a fan of Firefox since it was still called Phoenix/Firebird, but is seems it is declining nowadays, as it cannot keep up with Chromium-based browsers. I do not have a a lot faith that this bug will get fixed in the near future.

As I value my open tabs more than I value the convenience of opening a closed tab with a button instead of doing it via the context menu, I will unfortunately keep your extension disabled until Mozilla fixed the bug. It's a pity though, I really like your extension.

Thank you for your work. I hope to be able to use it once more in the near future.