It doesn't work, plain and simple. Maybe it has before recent FF updates. You click on it, and the list of closed tabs stays empty

Doesn't show more than 10 closed tabs, despite being able to set it higher in addon options. At 50 tabs shown, the list is empty. Need to be able to easily remove a tab from list like TabMix Plus or Session Manager did before Mozilla bastardized and killed Firefox with its stupid webextensions nonsense!