Z 3 z 5 gwězdkow pógódnośony

wót Danilo Fortunato dnja Okt. 23, 2018 · trajny wótkaz

Unfortunately this very useful add-on no longer works on Mozilla Thunderbird 60.2.1 with Lightning 6.2.2.1 (on Ubuntu Linux 16.04 64-bit).
The preferences panel is not shown.

I tried to manually modify the install.rdf file inside the add-on, in order to force the possibility to install it on Thunderbird 60.2.1.
The add-on can be installed, but it doesn't work at all.

I have the impression that this add-on is no longer supported by the Author.