I moved back to Firefox after an update to Vivaldi started lagging badly when I woke up my PC. Maybe it was an extension, but after disabling some of them I rea

I moved back to Firefox after an update to Vivaldi started lagging badly when I woke up my PC. Maybe it was an extension, but after disabling some of them I realised I don't really have time or inclination to find out. Another thing I didn't like was the re-purposing of the F6 button so it didn't highlight the URL any more (I guess I could change this; not sure) and the history page, which seemed quite confusing whenever I tried to use it. It's not a bad browser but neither is it so good I want to put up with those times it breaks or does something gratuitously different.