Comment 19 for bug 1721614

I've been having the same problem for a while. It is exactly as gpothier described. It is really an annoyance as the only way to get back to work normally, is to basically quit Firefox and start it up again.
I'm using Fedora 28, but the problem was the same on Fedora 27. I tested Fedora 29 too. Would be really nice to have to bug fixed at some point. If can provide any more info about the problem, please let me know.