UndoListInTabmenuToo.uc.js no Recently Closed Windows List in TABCONTEXTMENU

[Endor8]

In this Script something not works correctly>
https://github.com/alice0775/userChrome.js/blob/master/69/UndoListInTabmenuToo.uc.js

In the CONTEXTMENU the Entry and the list of Recently Closed Windows
is showed and it works fine.
But in the TABCONTEXTMENU the entry is showed but the list
is missing and the entry is greyed out.
Please take a look on it and I hope you are able to fix it.
Cheers
Endor

[Speravir]

Just as clarification: It works fine for recently closed tabs, though (until Firefox 69, for version 70 and upwards cf. #53).