Hi Finn,
thanks a lot for your feedback. The playlist import has been changed in a way that links to playlists can now be put into the general search bar instead of an extra import dialog. Videos can then be picked from the search results. I just tested it with this list and it worked fine for me:
https://www.youtube.com/watch?v=vzQlK65-aco&list=PL6XRrncXkMaXc35X93lCsrikqWg0xEFey
Regarding the import of likes… I’m actually not sure if that ever worked since i haven’t tried it myself. Could you provide me with a demo link that you tried to import?
I’ve heard that there might be issues with Firefox but so far i was not able to reproduce this issue. Do you have the impression that the instability is caused by certain actions that happen on the page (such as selecting a new video, importing a playlist…) Which plugins do you have installed in Firefox?
Florian