OT: firefox 20 does not display facebook correctly.

[joe at actionline.com]

Until recently, firefox displayed facebook correctly on my main
computer, but either firefox or facebook (I think facebook) has done
something to royally mess up the display.

Searching the 'net, I have found huge numbers of others reporting
the same problem.

Meanwhile, konqueror displays facebook correctly on the same
computer and monitor, so I know the problem is not with my computer
or monitor.

With my kvm switch, I can switch to a different computer using the
same monitor and firefox displays facebook correctly.

We have four other computers with various versions of firefox and
they all display facebook correctly.

I have cleared cache and cookies ... no help.
I have disabled hardware acceleration ... no help.
I have logged out and back in ... no help.
I have even reinstalling firefox ... no help.
I have tried firefox safe mode ... no help.

So why has firefox (the latest version 20) quit displaying facebook
correctly on the same computer and monitor on which it worked fine
not many days ago?  I rarely visit facebook, but I know within the
last few weeks it was working correctly.

My distro is Mint 13 with all the latest, most current updates
installed.

I have had no problem visiting any other websites.