I'm having the exact same problem. If I check the box marked 'Ignore
colors specified on web pages' and uncheck the box 'Use Windows
Colors', I should be able to choose my own background and foreground
colors.
I can still change the foreground (text) color on webpages but not the
background color! It stays white no matter what color I pick. So I can
have either a white background or the background color specified on
the web page, but not a background color of my own choosing!
This started immediately after I installed the latest IE6 security
update available this month (KB 832894) When I uninstalled it via
Control Panel, everything went back to normal.
I had the identical problem with the IE6 security update that was
available back in November (The number might have been KB 824145,
can't remember for certain). A poster on this newsgroup, back in
December, was having the exact same problem with the same security
update. He got a reply stating that MS was aware of the problem and
was looking into it.
About a month later, I downloaded the same security update again and
did not have the problem recur, so I assume whatever the problem was
at that time, it was fixed.
Lets hope this newest cumulative Security Update for IE6 is fixed
soon.