I've got Mozilla-Plugins like LastPass and NordVpn, where I can enter my username or my email account at first, but each time I try to switch to the next box , where I should be able to enter my Password, either by cursor or tab the Plugin window closes instantly. I have already tried it with every other plugin disabled to pinpoint if it's maybe a problem another plugin causes, but that's not it. OS: Ubuntu 18.04 LTS, but I had the same problem on Ubuntu 17.04 LTS So every idea is appreciated!