Same problem on an up-to-date ubuntu trusty. Now I downgraded from firefox:amd64 39.0+build5-0ubuntu0.14.04.1 back to 38.0+build3-0ubuntu0.14.04.1 and everything works again
Same problem on an up-to-date ubuntu trusty. Now I downgraded from firefox:amd64 39.0+build5- 0ubuntu0. 14.04.1 back to 38.0+build3- 0ubuntu0. 14.04.1 and everything works again