Has been requested so many times that I think I'll need a big fat information message directly on the Add-on page. The Mozilla API doesn't allow this and for me the top priority is to have both. Especially as I, myself, rarely use the menu. But if you search a bit on AMO you'll find Add-ons which have only the menu and have it on left click.

The only information, Mozilla gives me, is the timestamp where the tab was closed. I could add a feature which restores tabs that were closed "close to the recently closed tab". But I found that Firefox seems to be very flexible about how long it takes to close a tab. It can take 100ms but it can also take over 1 second.

I can make this an optional feature, disabled by default. Then the user can try different values for the time period by himself if he wants. But nonetheless: This shouldn't even be here. PLEASE: Always suggest features using GitHub!

Moved to: https://github.com/M-Reimer/undoclosetab/issues/74

The last update only modified handling of the icon drawing (pure optical change without any modification in functionality).
You can downgrade to any version easily on the installation page. Just if you want to try if the problem really was caused by an update.
But it's really difficult to track down problems here. It's usually better to get such issues reported on github.

It can do more. Try right-clicking. And it is meant for users that want to restore tabs with their mouse. No reason to give bad review.