I just came to tell you all that I think this new FireFox 57+ is fantastic. I run Kali in a VM for easily spinning up OpenVAS and running a scan. The GreenBone interface used to be a little slow. I manually installed the new FireFox and it completely changed my experience. The menus are more responsive and every page pops clean.

I followed the instructions here:
https://www.tecmint.com/install-fire...ntum-in-linux/

I found that the official FireFox repository PPA doesn't work because there is no Kali support. I had to install Firefox from tarball sources. Totally worth it.