I am using TenFourBird 38.9.0 which is based upon Thunderbird.
I am experimenting with address book import and export.
It works well for ldif but not for csv or tab delimited.
If I export and then try to import the same files they show in the window but are greyed out.
Is this a known bug with this version of Thunderbird and can it be overcome by editing the csv files?