Hawtio doesn't render properly in firefox or IE?

I suspect this is an environmental problem, because it is hard to believe
that this problem would not be noticed by many others...

I have been accessing hawtio for months via chrome and it works great. I
tried to give my boss a demo today of hawtio and he opened IE -- he logged
in and then was presented with an almost-blank screen. Hmm. He then opened
firefox and logged in; the screen looked almost correct except it was
missing the top bar in which you can click on "ActiveMQ".

I reproduced his issues on my PC. Is this a known issue, or is it just me?
Thanks!

John